He claimed he got caught up in looking for a book, but you could tell by his cramped right hand and wobbly knees that he'd been waxing the yogurt maker instead.
Another term for male masturbation, due to the act sounding much like that of yogurt being stirred.
The phrase "stirring the fruit-bottomed yogurt" may be used to denote a homosexual male masturbating, but is not required.