During the act of oral sex, specifically a blowjob, the blower bites the blowee's penis off. If performed correctly, only one bite is required. Additional bites may be added if botched. It is usually followed by a donkey punch.
"So this bitch totally tried to give me an angry claire last night."
"She bit your dick off?!"
"Nah, I pulled out and donkey punched her just in time."