Incest/Lesbianism. The term is generally used jokingly.
Girl to sister: Aw, I love you! *Pecks sister's lips*
Sister to girl: I love you, too!
Bystander: Fucking incesbians...
The Urban Dictionary Mug
One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.
Buy the mug