I know most bakers are solo, so this one might be a long shot, but it's worth trying!
-Some sort of setting where the girls would be together realistically. Like for a sleepover or hanging out after cheerleading practice or studying or whatever.
-One girl is a lesbian and seduces the straight girl, who didn't know how much she'd enjoy it. An element of not wanting to get caught would be cool too.
-The "seduction" part could be through sneaky touches, making out, whatever!
-A slow build-up would be awesome. Lots of kissing, tit play, sloooow stripping!
-The more "natural" of a feel to it, the better!