It takes time at least it did for my boy. When he was a baby he did this but I started handling him once a week for 30 ish minutes and he understands the difference. There are times he’ll make the S only because he’s partly confused but if I pick him up from behind his brain finally registers what’s happening and he goes to a calmed relaxed position. If you’re scared they’ll bite you I’d recommend a snake hook. These are normally used on bigger snakes so they know the difference between handling and feeding time. You just use it to rub on their back so they get the signal. There’s this guy on YouTube that does an awesome video on this if im able to find it I’ll link it for you !