I have to agree totally, if she seems like she is doing it because she should or treats it like a chore don't bother, but is she acts like she just can't get enough of your cock that is the real ...
I am the same way Lilith, I will tease myself, rub my cock through my pants, or out of my pants bringing myself close time after time (been known to do it for hours) sometimes I don't even let myself...