His clean fingers.
The man says, "I have a hard on but I didn't know you could smell it."
Disclaimer: I don't know how well this joke will work in English. What's yellow and lies in a pond? An excevator. You don't think this is funny? Neither does the operator.
Some people actually believe santa exist.
Your girlfriend has to chew before she swallows.
He's the one with the clean finger.
He has two clean fingers.