I don’t know if « routine » is the right term, again pardon my english...
Since I saw a girl tap dancing in the nude in a mid-90’s Rodney Moore flick, I’ve become interested in scenes/films where the girl is asked or given the opportunity - before, during or after sex - to do something “more”, like singing (even out of tune), jumping ropes, declaming verses, taming a tiger, playing the piano, or any kind of physical activity (sports, etc...). An example that springs to mind is Jennifer Steele performing her fire-spitting routine on video (haven’t seen them though, your opinions are welcome)..I also know the fitness / pumping-iron ladies from the BodyBuilders In Heat series (mixed feelings...).
Probably, the “porn-with-a-plot” ladies of the past were more likely to do that, but the free-wheeling, “cinema-vérité”, gonzo formula allows such situations too (see the Rodney example above).

More generally, would you think of any performer (from any era) that was known for something more than her sexual heat and was occasionnaly asked to perform "it" ?

In my mind, there are two categories :
1. situations that are not extraordinary per se but unexpected in the context of a porn movie
2. crazy performances that are unexpected and extraordinary, in ANY context

Any suggestions / memories ? Be it funny, sexy, boring, scorching or pathetic, I’ll take anything...(and don’t get me wrong, I’m a huge fan of wall-to-wall sex)

Hope that my twisted french bla-blah was translated correctly...