stereotype that a girl who has not taken lesbian 101 has not yet had a real lesbian experience. the stereotype is that the first time a girl really goes for another girl they will fall ridiculiously head over heels in love/infatuation, mixing up the pleasure of having sex with a girl/being in a female relationship/having a crush on a girl with being with THAT specific girl. especially a problem when one girl/lesbian/bi/queer female seduces/becomes involved with/is accused of seducing a girl who's never done anything with a girl before. ties into the joke: "what do lesbians bring on a second date? a uhaul." in that girls who are completing lesbian 101 may fall prone to overcommitment in the excitement of experiencing their first lesbian love. although sometimes lesbian 101 experiences can work out, like it's heterosexual counter part "frist love" it typically ends passionately and messily. completing lesbian 101 does not mean that you will major in women's studies, or to put it bluntly, become a lesbian.
jamie: hey amie! i hear you've got a moho girlfriend now, how's that workin out?
amie: oh my god she's amaaaaaaaaazing! i love her so much! i mean i know we've only been 3 days but i know she's the one! she, like, completes me! i've already picked out the name of our adopted children! and god is the sex mind blowing!!!
jamie:... dude, you are totally taking lesbian 101. have fun with that...
julie: yeah, so i really like this new chick lucy but uh...i'm afraid she hasn't taken lesbian 101, and i totally don't want to mess with that, you know?