Just got a quick question ?

Im still somewhat taming and introducing handling with my new spider ball......I have passed the getting tagged stage and also he has passed the tensing up stage when I go into the tank too pick him up which i think is good process so far ....... Handling him he seems awesome doesn't strike or anything just always wants to keep moving like crazy and flicking his tongue around he seems curious about everything around him ...... But anyways my question is : When I hold him and put my hand about underneath him about 3 inches back from his head why does he squeeze so tight ?...... Not going to lie he didn't constrict or anything but tonight he squeezed around my wrist a little to hard for my comfort !!...... Just wondering is this something normal or what do you think ?.....Im not worried about it or concerned as he is not constricting me or biting so I got nothing too worry about I'm just curious why he does this or they do this is its a common thing ...I don't know if age has anything too do with it but he is 7 months old ..

Any input would be great thanks,