Oh my gosh! YOU FUCKING FREAK!!! heheheheheheee
If it bothers her, then just dont do it. Shit, if the rest of it is ok with her then what THE FUCK are you complaining about?
Seriously, just say, "OK" and dont do it. She will either be relieved and glad that she could tell you and you not get your underoos in a bind over it OR she will actually be relieved and glad that she could tell you, you be cool with it and after a bit, ask you to do it if it pleases you so much.
It is about trust, intent and perception.