> My only experience with numbing is the dental anesthetic they use in your mouth, which I don't recall producing much sensations but it does noticeably take sensation away.

Those aren't narcotics (most likely). It was probably Novocaine or Lidocaine. Those drugs end in -caine because they're all part of the same family as cocaine, which is not actually a narcotic (but does have euphoric effects at sufficient dosing levels!).

Topical use of any of those drugs, however, will likely not produce euphoria.