Verb: The female version of tea-bagging.
Being bored at work one day, Bobbi decided to have a little fun with her coworkers by placing their coffee mugs against her naked labia, or lipsticking it to the man.
A phenomena whereby a male animal, for instance a dog, starts to get an erection and the reddy/pinky tip of the penis exposes itself, thus resembling lipstick. Not limited to the canine species, it has also been noticed in various species of African antelope and pachyderm.
"Hey Greggy, look at that male Kudu over there, it seems to be getting aroused". "Heck yes Jim, it's totally lipsticking".