If I'm just sitting around not doing much, then I don't feel them. I feel a little 'full' down there, but nothing extremely sexy. Just a kind of comfortable pressure.
When I'm moving around however, they feel VERY sexy! Its a kind of gentle teasing (which is a GREAT feeling if you're into that) and it really increases how wet you are. I even have the 'low movement' kind that only shake a bit.
Oh also, I forgot to mention, If you get the kind that are attached to each other by a silicone cord, then it can be a little difficult to insert them. I'm going to get the non attached ones next time.