Actually, this could be interesting.

You give in to her demands, the idea of fucking her with the roller skates on is pretty intriguing. You take off your pants and boxers to show her your dick. "Wow, it's pretty big..." Says the skater. You push her into the gym doors. Her roller skates move backwards hitting her back against the door almost making her fall. You grab her by the waste and insert your dick into her pussy. She moans in pleasure as your move in and out of her vagina. Even lower down, her feet are moving back and forth across the tiled street floor. As you pick up the pace, she starts to lose control more and more. "Don't let go... I'll f-fall..." She can barely get out a sentence between her moans.

"I'm about to cum." you warn her. "Please... cum inside of me. I need your seed." responds the girl. You both orgasm at the same time. The orgasm causes her lose her balance and fall backwards. Thankfully her large, plump ass softened the fall. "Thanks for that, take the roller skates off my feet, you earned them." You take her roller skates off and put them in your bag. "My names Rinka by the way, if I ever see you again, you should try putting my skates on."