Obviously, you did not hear the last two lines of that episode. In the episode you mentioned, Kramer did not go into his apartment with the male masseur from the hospital. Earlier in the show, Jerry was having trouble with the two-line phone Kramer had given him for his birthday. At the end, the innuendo was that Kramer was experimenting, but in the final dialogue, Kramer said, "He's the phone guy...(door slams, pause, door opens)..Not that there's anything wrong with that!"
I don't think that there was any connection at all between the episodes.
--Dave