On her.

Even though Alex said she has morning-after pills and promised to take one immediately, you don't want to risk knocking her up, however the remote chance. Fighting against your lizard-brain's need to reproduce, you yank your cock out just before it starts spurting thick ropes of jizz on her back and ass.

"Oh yeah..." she sighs.

After the last drop of cum drips to the floor, you collapse on top her, pressing your chest against her back.

"That was amazing!" she giggles.

"Yeah..." you grin like a lovesick schoolboy while you nuzzle against her neck.

"We should finish shower," she smiles. "I can't go to class with cum on me!"

You nod and pushing yourself off of her, realizing you had smeared yourself with your own cum when you leaned against her.

"Do you mind picking up more condoms after you finish work?" she giggles.

"Oh? I thought you're getting some?"

"So we won't run out for our second date tonight!" she laughs.