Kicking the Windmill

to kick a windmill is to imply that you have done something exceptionally morally inappropriate or ambiguous, (esp. sexually) but actually you are only referring to kicking a literal windmill

dude, last night i was over a sally's house and we were kicking the windmill so hard.

or

dude last night i kicked sally's windmill so hard she cried

by ktw4 October 2, 2010