This is 7 minutes in heaven: Part 1. Features the first two couples.

Percy's POV

"That was just a warm up. Are ya'll ready for Seven Minutes in Heaven?" Everyone nods. "Good." I reach under my bed and pull out a pen, a piece of paper and a hat. I rip the paper into five squares, as perfectly as possible, write my name on one of them, then put it in the hat.
"Guys, write your name on a piece of paper and put it in the hat." I tell them and pass everything to Jason. When the hat get's handed back to me, I give it to Ali.
"Ladies, you will draw a name. Don't say anything until everyone has one." I say.
Ali picks a name, then Thalia and Annabeth. After Annabeth passes the hat on, she pokes Thalia and whispers something to her. "Please?" She says quietly.
Thalia sighs and switches papers with her. I wonder who she got that made her want to switch..and who she wanted to switch for.
Ali's POV
Percy gets the hat back and puts it back under his bed. He turn to me. "Go ahead, sis. I assume you know the rules?"
I nod. "Me and the guy on this paper, we get seven minutes, in a closet, alone. To do whatever we want."
He nods. "Yep. Have fun."
I look at the paper one more time, excited about the name I got. Leo is scrawled in small letters in the middle. Percy stands at the closet and holds the door open.
I stand and walk around the circle, twice. I meet eyes with all of the guys. I stop in front of him. "Let's go." I grab his hand. He grins from ear to ear and happily follows me to the closet. The door is closed and locked.
I smash my lips against his, feeling his body temperature rising. He sets his hands on my ass, then kisses me back. I put my hands on his hips and grind him against me. His pants stiffen slightly.
"Your time starts...now!" Piper yells. Whoops, got a little head start.
"Thank..the gods..I got..you." I mumble between kisses.
His hands explore my body. "What do you wanna do?"
Instead of answering, I drop to my knees, pulling his pants down. I put the tip of his 7 inch cock into my mouth. I pump my hand and swirl my tongue around, pressing on random spots. After a few seconds, I cup his balls with my hand and push his whole member into my mouth, letting it slide down my throat. Precum dribbles out, helping me push it down. I pull my head away to breath and stroke his dick. "You wanna fuck me, Leo?" I ask quietly.
"Oh my gods, yes." He tells me.
"Five minutes!" Piper yells.
I pull down my pants and step one leg out. I spread my legs and put my forearms against the wall of the closet. Leo rubs his tip against my slit, then pushes it in, thrusting slightly. I supress a moan as he speeds up a little, sliding his full dick in and out of my wet pussy. His hands go to my waist and he pulls me to him as he thrusts, his balls gently hitting my clit.
He thrusts all the way in and holds his dick against my g-spot. My face gets red and I use one hand to massage my clit. "Fuck, Leo. You're so good." I whisper.
He grunts and moves his hips in a circle, rubbing my g-spot. He then pulls back and pounds me. Pressure builds up inside me.
"Yeah, yeah." I moan. "You like that, huh? You like pounding this slut pussy. You like teasing me. Fuck me, master. Fuck your little slut's pussy."
He thrusts hard two more times, then gets a good rythm going.
"Shit!" I whisper sharply as the pressure releases and I orgasm. My cum helps him thrust into me, lubing his dick up. His hands quickly heat up on my hips. I look back and he is gritting his teeth.
"I'm gonna.." He starts.
"Inside me." I beg.
"One minute!" Piper yells.
He thrusts hard again and holds the tip of his dick against my g-spot. I moan and he rubs that spot. I rub my clit, pressure quickly building, my walls contracting around his dick.
"Fuck!" We both moan and cum together. He gets on his knees and licks the cum from my pussy. I pull my pants up and suck the cum off of his dick, helping him with his pants. We connect our mouths, our tongues wrestling. I can taste both of our cum.
"Time's up!" Piper yells and Percy fligs the door open, just to see us kissing. I look around at everyone. Percy is scowling.
"What's wrong?" I ask him.
"Did you fuck?" He spits.
"That's for me to know and you to find out. Why?"
"The sink and shower started running and waves formed in the toilet and fountain."
"Oh." I look at Leo and we both sit down.
I lean against Leo and listen to his heartbeat until Thalia and Nico leave the closet.

Thalia's POV
All we did was kiss. Nothing good. I tried to, but he said he "didn't want to hurt me." Or he "wasn't ready for that kind of relationship." Ugh.

There it is. Naughty, naughty. I am now taking requests for Truth or Dare questions! Tell me who asks and who it is for. ~TLOO (the Lemons of Olympus)