You take your fingers back out of your ass. While looking around you new room, you notice a wrestling singlet hanging over the chair of Lucas' desk. "Wow, sporty family." You walk over to it and hold it in front of you. A grin starts to appear on your 12 year old face. You take off your pajamas and your underpants. You step into the holes of the singlet and pull it up until your member has disappeared under the fabric. As you look down you notice your package is clearly visible from the outside. "Heh, nice." You put the singlet on completely and adjust it till it sits just right.
You walk over to the small mirror on the wall. It's just big enough to see Lucas' entire body in it. You take your hand through your hair and grab your crotch with your other, making a sexy pose. "Damn, I look good in this" you say as you turn around and see your butt cheecks pressing tightly into the fabric. You give your ass a squeeze and tickle your small balls a little. "Ummmm... That's good!" You lower the singlet on one side and move your hand into it. You grab your cock and start stroking it. "Yeahhh..." You sit down on the ground to feel the fabric of the singlet stretch and push against your body. You then spread your legs to give yourself some room to play.
After stroking your cock for a couple of minutes you start to feel you heartbeat rise quickly. "Here it comes" you moan as Lucas' and ejaculate right into his singlet. "Ungggg" you moan and start panting. "So good...." You stroke the last of the cum out of your dick and into the singlet. A big wet spot is now clearly visible in the fabric. You take your hand and rub the spot while pressing it onto your belly to spread the cum further. "I am the best" you say to yourself as Lucas looks back at you in the mirror. You smile and sit tight for a moment to recover from the pleasure.
You stand up and look at your crotch in the mirror. "Sweaty and wet, just the way I like it." You move your finger over the wet fabric and put it into your mouth. "Tastes good! you say and lick your finger clean. You walk to the mirror and press your body against it. Moving your dick over the mirror, spreading the cum. "What do you want to do next Lucas?" You ask yourself in Lucas' innocent voice. "Whatever you want" you make him say back. You smile and think about what you should do next.