So long as he didn't touch any of the danger zones you could have just turned over and said "Oh my goodness, you beat us and we're dead! Now go tell momma how powerful you are!" and the moment that little one leaves the room, lock the door. Children come from the bowels of mischief, you must take all precautions when they're there.

OP talking to little brother in the future: OP - Remember that time when you thought my boyfriend and I were.... Brother - Just shut up! I was only little!

Well, that's why you generally don't have sex in places accessible to children, or while there is family home. Then these things wouldn't happen!

That is a horrible first threesome.

At least he didn't grab your boyfriend's 'stick' and hit you with it. Or did he?

Well, who gave up first? I wonderd how the kid felt when he noticed something unusual? Lil bro: i won i really beat my sister and her bf :D 20 years later Lil bro: why did i go into that room 20 years ago D:

Thinking its wrestling saved you the embarrassment

So, you were tag-teamed, eh?

Well at least you have a story tell 10 years later " hey remember when me and my bf were in the room under the covers and you.." * bro just walks out* Haha, should have kept the door locked

try locking the door or waiting till little bro goes to bed or goes out to play! clearly this is your parents house, so try having some respect.