She shivers when I touch her. What does that mean?

[Anonymous]

There is this girl im dating. I told her to make me a haircut (play with my hair). She sat on the back of the sofa i was sitting on. My head was between her legs. I told her to lift her legs so i can put my hands around them and started caressing them under her knees. Then i felt she was getting some kind of shivers. Her legs started shaking slightly like she was freezing (it was warm in the room). After a while she closed her legs around my neck (gently). I rested my head on tight and then in her belly and she kept shaking a little. Why was she doing that?

[Anonymous]

Over excitement, you send shivers down her spine with your touch, why don't you just ask her next time.

[guynextodoor]

she might be ticklish