In the first episode of M*A*S*H, you see Hawkeye dancing with Lt. Dish and Margaret makes a comment to him. He replies by calling her Hotlips. She gives him a nasty look. Later in the episode General Hammond sees Margaret when he enters the tent during the nurse raffle and calls her Hotlips. Hawkeye and Trapper say "Hotlips?" with a surprised tone like they've learned a new nickname for her.