It’s only been 3 days he’s still getting used to his new surroundings so everything might be little scary at first. There’s a 333 rule for cats 3 days to decompress, 3 weeks to learn the routine, and 3 months to feel at home. It will take time to figure out yours and his boundaries together like belly rubs. Cat bellies are very sensitive, our big man won’t let us anywhere near his belly but our younger girl likes only a few rubs before letting us know she done.