The practice of putting once lips on a pair of labias, following a buzzing noise to create a sound similar to the trumpet. Sounds may be similar to that of a folded leaf whistle, but with the added sound effects of wetness.
Richard: Hey Max i had such a great time Lumpeting you last night.
Max: Oh no problem you can lumpet me anytime.
Richard: Really? How about tommorow?
Max: Sure babe just meet me by my house.