Relieve yourself behind the bench.

There's absolutely no way you can continue to walk around this park full of people with an orgasm so built-up. The only way you figure is to release that pressure, and then hopefully the panties won't bother you nearly as much. You look back and forth to see who's around you. From what you can tell, you're at the edge of the park, and the only travellers are a distance in front of you. If you stand behind the bench, it'll cover you perfectly.

Slowly, you slide your hand up your leg, pulling up your skirt to caress the edge of what your slim panties cover. You push the fabric out from your lips and begin to slide your fingers in and out instead. Your cheeks glow red as your breathing speeds up. You look around again, and nobody seems to be noticing... In fact, you seem to be getting even more aroused at the thought of where you are. You've never masturbated in public before.

Faster you move your fingers, bringing you closer to the orgasm. As long as nobody walks by, you can finish and be on your way. Almost. Almost. You're so close! Your eyes begin to close, and...