Oh, Krystal's kissed him on more than one occasion. They have a weird relationship, where Tommy clearly wants to bang Krystal but doesn't know where to even begin, and Krystal has just enough self-respect not to fuck Tommy but lets him cuddle with her after they go out drinking. They are genuinely good friends, because Tommy is such a bumbling sped, he put all his cards on the table like five years ago.
If Tommy ever gets laid, he'll stumble into it like Mr. Bean stumbles into traffic. He'd never do anything uncouth to a pretty lady.