My partner likes it when I stick my tongue inside his ear(s) and lick his ear lobe(s).
Any erogenous zone ... and no, I don't mean genital zone (well, that, too)
Anywhere the skin is thinnest - wrists, inner arms, back of knees, inner thighs, temples, behind the ears, groin area where the leg joins the body, lower back ... anywhere the skin is thinnest, that's where the nerve endings are right there -
Licks, nibbles, light touch (fingernails work great) ... experiment and have fun ;)
ps - these are also the areas that massage can be tricky in - too heavy a touch can hurt, and too light will tickle.
Oh, yeah - ticklish areas are great, too :)