I believe I’ve finally found a case where the above weak English pun on “martial arts” actually works in Japanese. Staff fighting in Japan and Okinawa is known as boujutsu, written 棒術 (pole + technique). Identical pronunciation with different kanji, however, yields 房術 (room + technique), meaning “the art of lovemaking”.

This appears to be a deliberate pun, with the more usual words for lovemaking being bouchuujutsu 房中術 (“within a room” + technique) or keiboujutsu 閨房術 (bedroom + technique). A bit of casual wiki-surfing suggests that the pun comes from the popular Naughty Ninja Girl genre of novels and movies (much the way that the words ninja and kunoichi are basically post-WWII creations, along with the scary-black-pajamas look).