I guess I should also reply to this seriously in a way that isn't about feet wine. Sans is a fan of studying magic in general and finds the differences between magic in different universes very interesting, so he's down for all of this.

His specialties: Time/space based physics magic, both monster and fae varieties. He's also good at conjuring/summoning magical constructs. Also if you wanna HULK OUT and turn into a big ol' animal, he can give you some pro tips, because he got an affinity for bestial magic as part of a contract with the Ringmaster. That's how he summons his magical dogs

Would like to learn: Wards, mental defense, protection spells, and to experiment with his angelic magic since that's still pretty new.

Willing to teach: Sans has taught a few people how to do magical tricks. He taught joker how to make teleportation charms, and he's been schooling Lambert in the ways of turning into a big fuck-off monster. He's essentially got a PHD in magic and has been working in a lab setting since he was a teenager, and so he has a pretty scientific/mathematical approach to magic. He's not the best teacher but he certainly isn't the worst - his biggest issue is that he may or may not start nerding out about advance concepts his student won't understand.