Little Johnny keeps asking his Dad for a television in his bedroom, to which his Dad keeps saying "No". But after a lot of nagging, Dad agrees and says, "OK". 

Several nights later Johnny comes downstairs and asks, "Dad, what's Love, Juice?" 

Dad is horrified, and after looking at Mum who's also gob smacked, proceeds to give his son a full explanation of the 'facts of life'. 

Johnny now sits on sofa with his mouth open in amazement. 

Dad asks "So what is it you've been watching then Son?" 

And Johnny replies, "Wimbledon."