Question: what do lesbians bring on a second date?
Answer: a U-haul.
The informant said she has both heard and told this joke on multiple occasions, by and among members of the Los Angeles gay and lesbian community. She also noted that, this is the kind of joke thats reeeaaaallly funny when everyones drunk.
The joke here is not a play on words. The incongruity is appropriate not by logic, but by being such an exaggerated stereotype. It is poking fun at the stereotype of women being over trusting, emotional and overly eager to commit, and therefore have a tendency to prematurely gauge the depth and seriousness of a relationship. According to this joke, lesbians are ready to move in after just having met their partner just one date prior.
This joke could easily be varied by replacing lesbians with women, and would still have a similar effect, but because the lesbian relationship is stereotypically seen all the more wrought with drama, jealousy and bitchiness simply because there are only women involved, the female stereotype is more exaggerated with the use of the lesbian demographic, and thus the humor is more exaggerated as well.