While the idea of this is "legal" I find myself a bit creeped by it. Erin (40ish) is visiting her daughter at college, she sleeps with a woman she meets at a bar (who is 21) and then finds out Cassie is her daughter's new best friend. We then see how the two "cannot help themselves" when near each other.
As a 40ish person who just moved my younger brother's daughter to her college town I feel this story and felt too uncomfortable to cont.