I prefer them warm and soft. Ideally short toes.
I find if I soften them up a bit with a nice hot oil massage first for about 20minutes or so, the girls seem to enjoy the actual foot work better. If the feet are not properly prepared, and you get your tongue on them pre maturely, it may tickle or be not so pleasant for the receiver.
If the feet have been worked on for a while, often a full body relaxation response takes place and when the toes finally go into your mouth it is simply heaven for the girls.
You usually can tell by the moans, groans. It they shriek to high heaven you'll know you are doing a perfect job.
Just my five cents on the subject
John
