Occasionally, a massage can be feeling great and then the therapist gets to a spot that just tickles. Some people can handle the tickle and they get a nice laugh, but for others it causes discomfort. A tickle is actually the body's way of saying that the nerves are registering something but are not sure what or why. Fortunately, a massage therapist can work around this feeling.
If there is a ticklish spot, the therapist can change techniques or the amount of pressure used over that spot to try and calm the tickle or "train" the nerves on what they should expect and teach them that the sensation is ok. If the area is just too sensitive, the spot can be skipped altogether. The person receiving a massage usually knows if they have any wildly sensitive or ticklish spots, so don't be afraid of warning the therapist ahead of time. Sometimes those spots can pop up unexpectedly, and if that happens, don't be afraid of explaining that it is ticklish, so the therapist can adjust.