When a Male or Female "licks out" or gives oral sex to a Female while she has her period or menstrual cycle. This results in a red sauce-like liquid around their mouth. Because Dolmio is a red sauce, the term "Dolmio Smile" is used.
Carol: I enjoyed you licking me out last night.
Paul: It may have been good for you, but I got a Dolmio Smile from it!