Sexual act where someone takes it orally and anally/vaginally at the same time. When 2 people bookend someone, they are bookshelfing or have bookshelved them.
"Were gonna go bookshelf this girl!" "Oh man me and Phil Bookshelved this slut last night!" "So, when are you gonna let me and my boy bookshelf ya?" "I walked in on my mom being bookshelved by my best friend and my dad!"
by BodyDropper July 27, 2008