Yeah... of course it is.

When he peeks in the doorway, he can't help but gasp. Charlie turns and glares at Ed as she slowly, oh so gradually, lowers herself into the splits. "Oh it's you. Hey freak. Come to perv on me?"

He stutters helplessly, not sure where to look, and manages to stammer out, "M-mum and D-d-dad?" Charlie rolls her eyes. "Can't even speak English he's so horny for me, jesus. They've gone to a party with their loser church friends. They'll be gone for hours and hours and hours..." She turns back to the TV and settles into a pose that requires her to be on all fours with her bum pointed directly at the doorway. She starts to sway her hips lightly. Ed gulps and backs away - but it doesn't take long for him to come back and watch her, mouth agape, sizeable bulge growing. He thinks he's being sneaky, but from the angle of the CCTV camera you can see the glint in Charlie's eye, and you're pretty sure she knows.

Charlie, legs flat on the mat, arches her back in a way that looks like it shouldn't be physically possible and lets out a long groan, and without even seeming to think about it, Ed starts running a hand up and down his crotch. Looks like he's breathing pretty heavily. You are too. How far are these two perverts going to take it?!

Suddenly Charlie, still bent back like a longbow, opens her eyes and sees (upside down) her step-brother standing half in the doorway, rubbing his crotch. She gasps unconvincingly.