Spur of the moment thing here ;) Lyrics are Ronan Keating's 'Father and Son' (I may have left some parts out, possibly if they were repeated)
Also, there are loads of different time frames here, but it's not confusing (I don't think anyways :S)

Father:
It's not time to make a change,
Just relax, take it easy.
You're still young, that's your fault,
There's so much you have to know.
Find a girl, settle down,
If you want you can marry.
Look at me, I am old, but I'm happy.

Gibbs watched as DiNozzo bounced into the bullpen, full of life and a giant smile plastered on his face,

"Good mornin' Boss!" He chirruped, ignoring the eye rolling McGee had sent him. They all pretty much guessed what was going on. Every week he was like this, toward the end of it rather moody. Possibly because he always managed to peg a different woman every week. Gibbs just sighed fondly, sparing his senior field agent a small smile as DiNozzo beamed over brightly, a spark in his eyes,

"What's her name?" Kate asked, a slightly smug tone to her voice. Tony turned to her and asked politely,

"And why would it have to be a woman for me to be happy?" Kate raised her eyebrows and shot back, snidely,

"Because you're you, DiNozzo. A womanizing beer swelling frat boy who only ever rises to the occasion or responsibility when there's a pretty girl involved." Tony sobered up somewhat, his eyes dulling. He sat down at his desk and started to type softly at his computer. Gibbs shook his head. Ok, so what Kate said had been marginally true, but Tony always went above and beyond the call of duty, giving everything 100 percent even when there wasn't a pretty girl in sight,

"Kate, he's just a young man, what can you expect?" Gibbs chided Kate, who blushed slightly and put her head down as well, starting her work.

Tony looked up and gave Gibbs a small smile of gratitude, which was returned with warmth.

Father:
I was once like you are now, and I know that it's not easy,
To be calm when you've found something going on.
But take your time, think a lot,
Why, think of everything you've got.
For you will still be here tomorrow, but your dreams may not.

"I d-don't understand it Gibbs," Tony murmured, looking into his Boss' eyes as he sunk to the floor near the stairwell, "W-why would sh-she leave us? What did w-we do?" His heartbroken sobbing that followed was agonizing for Gibbs to listen to, but he sat next to the younger man and explained gently,

"Kate wouldn't have left us on purpose Tony, you know that. She was just... caught in the middle. In the wrong place at the wrong time." Tony shook his head, tears spilling down his cheeks,

"No, right place, wrong time. Or wrong place right time. She stopped a bullet for you Boss." Gibbs nodded, a lump rising in his throat, but replied,

"I know it's hard Tony, but we have to focus on the case. We can't let Ari get away with this. Just think of what's still here, all the good memories she left you with." Tony sniffed but couldn't stop the oncoming sobs as he pushed his face weakly into Gibbs' chest as the older man put his arms around the young agent, trying to give him some sort of life line to hang onto,

"I've still got you Boss..." He said weakly, shock catching up with him, causing him to fall asleep as he said this, but not before catching Gibbs' answer to that statement,

"And I've still got you Son. I'll always have your six."

Son:
How can I try to explain, when I do he turns away again.
It's always been the same, same old story.
From the moment I could talk I was ordered to listen.
Now there's a way and I know that I have to go away.
I know I have to go.

Little Anthony DiNozzo stared upwards in fright as his Father sat at his vast, expensive oak desk, sipping a glass of whisky or something, giving Tony the filthiest look he'd ever been given,

"I hope you understand you've done wrong?" Tony stuttered out slowly,

"B-but Father, I didn't t-touch the v-vase, i-it was al-already..." Anthony DiNozzo Senior looked at him, hatred spilling from his eyes,

"Don't give me that excuse boy, it's your fault. Remember that? Your fault. Now repeat, who's fault is it?"

"Mine." Little Anthony whispered, before being ordered to turn around, ready for his punishment......

"Tony? Tony?" Tony woke up from where he had been sleeping at his desk, his head resting on his arms. Looking around blearily he saw it was only him and Gibbs in the office,

"Hey Boss. What's happening?" Gibbs gave him a look,

"You were muttering in your sleep, then almost yelling. You almost fell off your chair." Tony blushed, but was thankful that he was here, with his anchor, giving him a way out of his past, keeping him there,

"You ok?" Gibbs asked. Anyone who knew him well enough could tell he was concerned, his eyes wrinkled ever so slightly and his tone calmer than usual. Tony smiled warmly at him and replied,

"Now I am." Gibbs nodded slightly and waited until Tony was asleep again before studying him, making sure he was no longer having nightmares.

Son:
All the times that I cried, keeping all the things I knew inside,
It's hard, but it's harder to ignore it.
If they were right, I'd agree, but it's them you know not me.
Now there's a way and I know that I have to go away.
I know I have to go.

Tony pulled himself into a ball and cried harder. Paula was dead because of him. He knew that. If he had gone instead of her, pushing that terrorist through the trap-door, then she'd still be alive. Even if that meant he was...

"Don't even think it DiNozzo." A warning was issued from the corner. He jumped up in fright, almost cracking his head off one of the tables,

"Boss! I didn't... I thought, shouldn't you be home? You said..."

"You're not the only one who works late Tony." Gibbs sighed, going to sit on the chair Tony had abandoned at his desk, opting instead for the floor, which was obviously easier to cry on. Tony blinked, pushing any more tears away and asked, quietly,

"How did you know what I was thinking?" Gibbs put a gentle hand on his agent's head, slowly moving his fingers around, making Tony relax as his hair was pushed back and forth,

"Your thoughts are only too clear sometimes DiNozzo." In truth, however much he knew Tony was beating himself up about Paula, he still wasn't sure whether or not he wanted to do anything about it. Tony seemed happy, joking around with Abby, making fun of McGee, antagonizing/flirting with Ziva, so Gibbs assumed he'd sorted himself out. Thinking that, he almost head slapped himself. You should never assume. It could even put lives in jeopardy.

The only reason he'd come back late at night, as he knew DiNozzo was here, was because the rest of the team were as worried as he had been. They'd all had their own suspicions of how Tony felt, and what he was thinking, but they all knew he felt guilty. They managed to convince him to come back and talk to Tony, all completely certain in the fact that, in Abby's words, 'Tony only opens up properly when it's just you Bossman.'

"Tony, listen to me. It's not your fault. Look at me." Tony looked up, his arms wrapped around his knees, his head leaning against Gibbs' leg. His eyes were rimmed with red and he still had tears clinging to his eyelashes,

"Forgive yourself Tony. God knows why you feel guilty about this, but it's plain to see and we're all worried about you. Tony," He said again, as the younger man's gaze had dropped, "I'm worried about you." Tony sniffed and pushed his head deeper onto Gibbs' leg, whimpering,

"I should have done something Boss." Gibbs shook his head,

"Get rid of these thoughts Tony."

"Is that an order?" Tony asked, his tone not quite so dull, and Gibbs' heart leapt slightly with hope that he'd get through this,

"Damn straight DiNozzo. I'm offering you a way out with this. Take it. Forgive yourself." Tony slowly stood up, looking tired and serious, an older than he ever thought could be possible.

"Thanks Boss." He mumbled. Gibbs stood up as well and wrapped his arms around him, a hug that Tony instantly leant into,

"Aw hell DiNozzo," Gibbs said to him, as he held the other man safe in his embrace, "I don't need thanks for something that doesn't take up any of my time or emotions. Not if I've got them all ready, specially for you."

Tadaa :D Well, that didn't take too long, and I'm quite pleased with it tbh, please review, I'm never too good at songfics ^^