Sticky situation

So one of my good friends goes out with my girlfriends sister,

Last weekend me him and like 10 of the lads were on a mad St Patrick’s day drinking session and it got pretty hairy as we started drinking at 10am,…

Anyways, by the time we get to the club, so we are all well steaming at this point and we are all air humping to some filthy techno.. some nearby girls found it funny and they were laughing their asses off, so my drunken self went over and started air humping them, which they all found funny too.. no big deal as I thought,

Well now I’m after getting a call from my mate who goes out with my girlfriend sister saying he accidentally told the sister that I was air-humping women in the nightclub,

So now I have to have a talk with my girlfriend letting her know before her sister tells her that she heard I was going around the nightclub humping women… ummm what do I do