I echo what Blue Line said. Sure, I'm always going to be ticklish to a degree- but that degree varies WIDELY based on who's touching me. The connection you have with the person can dictate how ticklish you are in many cases. I think it probably also may depend on the amount of mind screwing the...
I'd suggest investing in a good set of cuffs, then use rope to tie. Good quality cuffs are worth their weight in gold, and allow for many different positions.