Marko was annoyed when he had to leave his hot, fertile professor to come bust the hot goth brat out of jail. Now she's in his debt, and she's offering up her backdoor V in thanks. Marko wants her to take it deep, and the bratty woman loves it rough.
It's the perfect release before he goes to see his art professor again, so that he can show her everything he's learned. He'll repay the favour of getting him on the exclusive hookup app with his tongue before filling her up with his seed.