Yeah, I've moved snails lots before! I pulled a little, wiggled a little, did all the usual stuff... never did it with tongs before though and never will again, too hard to gauge the force. The worst part is he just sat there without his shell for like 2 hours before I went to bed. I could barely look in the tank, I felt so bad. If nothing finished him off overnight and he's still sitting there looking at me without his shell I might freak out a little.
His buddy musta been watching though, as soon as I grabbed him (by hand) he let go. He knew what was good for him.