Its a term used in English to describe an erect penis. Thank you.
3 Answers
Sixty-odd years ago I learned the phrase "pull a boner" , meaning "make a stupid mistake", from American movies. This would be ミスをする (from English "mistake"), 失敗する or 間違える in Japanese. Probably best to try not to confuse the two senses of "boner". By the way, 勃起 is the formal term, corresponding to "erection"in English. I'm sure there must be a Japanese slang term, but don't know what it is.