I'm pretty strong and I haven't been held down and tickled since I was a little kid. It would definitely take more than one. I'm only into getting tickled by women but I don't think I'd mind if a guy helped hold me down. I get excited by bondage though, and love being tied up. The more immobile the better! There's light bondage and then there's real bondage. It's not the same if I know I can escape easily. I once had my arms bound to the bed and wrists bound together, and I still managed to overpower my 'ler, hold her against my body, and tickle her until she safeworded. (Granted, she was 5'2" and <100 lbs.) But in that case the bondage didn't do much, obviously. I just bought some heavy-duty restraints and will be trying them out soon though!
As a 'ler, wrestling and overpowering a 'lee is fun, I have to admit. Holding down the 'lee's arms with my legs and tickling her upperbody is really hot. Because I'm big, though, a little bondage goes a long way. It becomes MUCH easier to hold the feet or arms still if they're cuffed together. You get both squirming and control that way. It's highly erotic with a partner.
For real tickling creativity, heavy bondage is called for. When I'm using a Sonicare or other toy, sometimes I want to focus on delivering/feeling maximum sensation rather than worry about the 'lee/myself trashing about. With a Sonicare on the feet, e.g, it's most effective to hold the toes. You can only do that effectively if the 'lee can't mice his/her legs.
I love heavy bondage for "tickle-torture" scenarios like interrogation. So hot.