well for one if she has deep shallow breathing, its heavy and slow. If she tend to figet or constantly moving her legs. Her choice of words would be more Sexual in nature. If she bites her lips from time to time. this i know so well since i been experimenting with this since i was 16 years old. (i was a curious teenager and i had a female bestfriend that helped me
).then she is aroused or Nervious or eager (or all 3 at the same time) Try this next time for more kino and i know it will surly arouse her. The back of the knee and the back of the tricep of her arms are very sensetive. If you are sitting next to her with your arms over her shoulders, gently brush the back of her arms or the sides slowly. Or get her to let you "tickel" the back of her knee ,be like " hey can i see if this is tickelish on you?" she might be or might not and ask "how does that feel?" another way is to use her own mind against her. females has one of the best imaginary minds