Depends on the situation i think , the jump and surprise tickle attack is more with friends and of short duration or if ure realy close meaby longer and with bonds like say a scarf or ductape and the planning is more when u would meet up with total strangers for a tickle session.
Or if ure reay daring , plan to kidnap a friend and tickle torture him/her for a while and hope they don't get mad and brake up ^^