I really like to use my mouth to tickle but is there any other way to make it feel even more ticklish?
The most I know is that sucking on the toes tickles super bad but that's the extent of my experience.
I second what
@Doriansenigma said about grazing the teeth and nibbling. You can do that on the toes, sides of the feet, arches, heels, and everywhere really. This tends to surprise some people and make them jump and yelp. With the tongue itself, you can weave it between and around the toes, which tends to be a ticklish hot spot. Use the tip of your tongue on the rest of the foot and vary up the pressure to reduce chances of desensitization. Each person is different in terms of what parts are most sensitive and what pressure works best. Keep your mouth and tongue well-hydrated . The slicker, the more likely it is to tickle. If you're prone to dry mouth, or you want to increase the slickness, you can use food-grade coconut oil as a lubricant (assuming neither party has a sensitivity to it).
Or is there any way to properly pin or restrain someone that I'm licking? Cause sometimes I get kicked in the face lol.
The absolute best way is probably to use secure stocks with toe ties, though that is not accessible to everyone. Even then, sometimes a foot comes loose from the toes on some designs and setups. Aside from that, I think one of the best ways is to use strong ankle cuffs anchored to a hard point with the legs stretched out as far as is comfortably possible. When the leg is fully stretched out like that, you can't really be kicked by the most powerful muscles of the leg, though the ankle still has some mobility, it's strength is reduced some due to the chain of muscles being stretched out on the back of the legs. You can often get less ankle mobility by tying someone this way, but face down. The trade-off is that the foot is not in it's most vulnerable position (it ends up slightly scrunched up with ankle at least slightly bent).
No matter how you slice it, it can be really hard to tickle ticklish feet with your mouth without the risk of getting kicked. I've had my own fair share of injuries from it for sure. It's almost like nature doesn't want stuff messing with our feet... almost! 😂