Lil Wayne was ready to physically attack Drake for screwing his girlfriend ... and Wayne says this himself in a book proposal he's shopping.
TMZ has obtained a portion of the proposal Wayne has sent to various publishing houses, and his story is crazy. Wayne claims while he was serving time at Rikers Island for gun possession, Drake visited him and glibly confessed, saying, "Yeah, it's true. Don't f*** with her like that cause I did f*** her."