So as a kid I loved Sesame Street. But I used to watch Rainbow as well.
Today, I came across this clip:
and it shocked the bejesus out of me and I kept checking to see if it was an over dub. Guess it wasn't
"In 1979, the cast and crew of Rainbow made a special edition for the Thames TV staff Christmas tape, sometimes referred to as the "Twangers" episode. This show featured plenty of intended sexual innuendo (beginning with Zippy peeling a banana, saying "One skin, two skin, three skin, four..." before being interrupted), and although not shown at the time (as it was never intended to air), it has since been aired for the amusement of those who grew up with the show. The clip became famous after being aired on Victor Lewis-Smith's Channel 4 programme TV Offal (1997) and was jokingly referred to as 'the pilot episode', which it clearly wasn't as Geoffrey Hayes was presenter at the time. (It should be noted that the external page, linked below, erroneously claims that the episode was publicly broadcast as a regular episode.)
TV Offal also broadcast some very risqué material featuring members of the cast when they were guests on a variety show hosted by comedian Jim Davidson in the 1980's; the sketch in question, which featured former children's TV presenter Tommy Boyd, asking a question about Adam and Eve. Boyd and Davidson used some profanities in the sketch, along with some innuendo from George (presumably again not intended for broadcast like the above), but the most shocking moment was when Zippy exclaimed to Geoffrey: "The fucking Garden of Eden!" .
Comedian Bobby Davro also parodied Rainbow as a comedy sketch in his own TV series in the early-1990s, playing the part of Geoffrey alongside exaggerated versions of Bungle and the puppets, which contained some mild sexual innuendo. (Davro had appeared in a regular edition of the show, in which he performed amusing impressions of the characters in front of them.)"