Pull your panties aside and bend over

You quickly reach back and bunch up the back of your thong, pulling it to the side. "Bend over and hold the rail so I can see, slut," Marina instructs you. You feel for the handicap rail in front of you. It's quite low on the wall, so you have to bend way over, spreading your legs slightly and thrusting your bared hole backwards. You jump slightly when she spits on your ass and starts rubbing against your entrance with a fingertip. "Open up for me," she hums.

The tip of her finger slips inside you. You've stretched yourself out enough that it's pretty comfortable, and she adds a second finger with some more spit. "I bet you're harder than ever aren't you?" Marina goads. "Let me see." You reach back and pull your panties down so that they stretch between your thighs, just below your ass in the back and your tightening balls in the front. You are painfully aroused, and the rougher Marina's fingering gets, the more pleasurable it is.