Yep.

You do, you're now right behind her and even though your position is precarious it seems as though nobody has actually noticed.

Chantelle starts backing up to move towards defence but you're right at the back of the court so there's nowhere for you to go. Her ass is now millimetres away from your erection, you're getting more and more turned on and you glance over to Sophie's who's red thong is showing, she winks at you and you try to again look away and see Jess, slip over, revealing a pair of black panties under her white tennis skirt.

This is all too much, you are losing control and your penis is straining madly at the fabric of the shorts, you're the most turned on you have ever been and you are finding it impossible to remain composed. Chantelle, unaware of goings on behind her, takes one more step back, planting her ass against the bulge in your shorts. From Sophie and Jess' perspective, who were both watching, they see her face in a look of confusion, eyes widening.

It's taken you over the edge, you can't handle it anymore. You grab your sister's waist, clearly the right thing to do is push her away before something terrible happens.