In my community college Judo class during groundwork drills, my uke squeezed my sides and hips a bit, which tickled me even through the gi since tickle wise my stomach/sides are my weak points. Has this ever happened to anyone else?
No. However, check these out for examples of when it does happen. BTW, there's at least one instructor I've seen in youtube videos who using tickling in his martial arts practice and teaches others to as well.