I have a wide range of reactions depending on the situation. For instance if something about the top really bothers me or the situation is uncomfortable, I am not very ticklish at all. Realizing this, I have learned to relax (and avoid unpleasant situations). The skill level of the top is important. I have had some tops who approached tickling based on their own fetish needs and not what was working on me. Sort of a "well this always works, why doesn't it work on you?" reaction when I didn't respond well. My partner can make me laugh pretty easily. I have know some very skilled ticklers who could make me insane with laughter, screaming, etc. Good bondge helps too.
If you are new to bottoming and looking for a top, I have a few suggestions. First, be sure you are playing with someone you like and preferably someone who turns you on. Secondly, it is better if the top is experienced as a tickler. If not, don't expect fireworks the first time. It may take the top a while to figure out what works on you and what tickling is all about. Third, I encourage you to react when you feel something that is ticklish. Don't hold back because those reactions give a lot of clues about what works best on you. I don't mean to give orders or suggestions (bring out the gag). I mean jump, wiggle, grunt, giggle, do what ever you feel like doing when the top hits the right spot.
Finally, if tickling isn't getting a good reaction, a creative top will often switch to other things and come back to tickling later. So maybe you will get your nipples played with or get licked or kissed or other things that get you excited. Then tickling can be reintroduced while you are reacting to other things. Often that will help you react more.
Laughter may not be the only reaction you have, but if you are having fun and reacting, that is the important thing.
JerryB