I came a across a Reddit comment that asked whether or not Superman is ticklish. One commenter replied with this image, but that doesn't really answer the question.
Although it sounded like a stupid question at first, tickling someone could certainly be used to bring their guard down and make them easier to incapacitate.
I am not at all familiar with Superman lore, but is there anything to suggest that he is immune to tickle attacks or is he ticklish like normal people would be?
No. The original continuity Superman doesn't appear to be ticklish. You basically need to hit him with bullets or lightning bolts before he can even feel it but generally when he says that he's ticklish, he's usually showing off or trying to denigrate an opponent.
Mocking an opponent
Showing off.
Mocking an opponent
Mocking opponents
In this internal dialogue he explicitly states that he's not ticklish.
All bets are off in the New 52 continuity. Superboy appears in Superman Rebirth #6 being tickled by his mummy.
Superboy Prime basically has the same powers as Superman and he's also not above mocking his opponents
