Keep Going

You don't let her mind games get to you and you continue your rush forward. You ram your knee directly into her groin, but your victory is short lived as you feel her knee catch both of your nuts.

You both gasp at the same time, but neither of you back down

"You never could take much punishment" she said "Give up now and I'll make it as painless as humanly possible"

You retract your knee and she does the same.

However you refuse to let your sister show you up again and grab her through her thin cloth and squeeze her clit for all your worth.

You're not surprised at all to find her able to close her fist around both your balls and squeeze the hell out of them.

You feel yourself about to throw up, with the pain being too intense