Gotta admit, this is a pretty hot situation to find oneself in, being stuffed in the panties of a giant hot gal while she gets frisky with another? Yus, niiiiiiice stuff.
It comes so natural to them XD. No glancing down, no pensive hanlding, it's just straight 'guy goes down the underwear, then we fuck'. That's how you know you've found the right partner nya, bein frisky and kinky comes naturally, nya~