Well you could try the clasic denie denie denie

or

you can say
"look we are boyfriend and girlfriend and kissing is what we do! if you dont like then o well, we are going to do it anyway"

or

You could get to them first and tell the truth and hope that this admioral act will score you a few points with them.

__________________
The Seven Deadly Sins:
Lust,Gluttony, Greed, Sloath, Wrath, Envy, Pride.
We're guilty of them all. O well looks like we're all going to hell! (=you)