Vibrator (device designed to stimulate a woman's genitals).
Back-of-the-book; denoting those stamps in a catalogue that are not used for the payment of regular postage fees, and are displayed separately in the catalogue after that listing; the division between these two groups varies with the publisher.
Coitus or genital-genital sexual contact.
Sexual interaction, usually involving vaginal and/or anal and/or oral penetration, between at least two organisms.