Well, first of all, he needs better lines. Not only are his jokes cheesy, but he’s also implying that he’s Speedy Gonzales in the bedroom. The next time he uses that line, say, “Really? Ten minutes is all you’ll need? I’ll pass.” Give it back to him and see how he reacts.
Is he into you? Possibly. He could have suddenly realized his feelings for you, and this is his awkward way of letting you know. He could be trying to steer the relationship into the “friends with benefits” territory, and making jokes to gauge your reaction to the idea of sleeping with him. Or he could just be making stupid jokes. Maybe he feels comfortable enough with you to make crass jokes. If it makes you uncomfortable, tell him to cut it out. If he persists, firmly tell him to stop it, that you’re not interested in him in that way. It sounds like he’s an okay guy, so hopefully he’ll take the hint. But definitely tell him he needs to work on his zingers.