That little vixen Marta was none other than Yvonne Craig aka “Batgirl.”
But that scene was her trying to get Kirk to do something for her at the request of Garth (played by Steve Ihnat who sadly died at age 32).
But Kirk was on to her game and pushed her out of the bed without doing the nasty. So Marta doesn’t count.
Oh what nerds we ST fans be :)