http://sparrowa7io5pz6ud3ehqzosvepbxbxt2zphmkjsylp2zgxooko23pqd.onion/docs/spending-privately.html
It’s similar to an xpub, except that no information about a wallet can be learned from it.
In this sense, it is safe to share. The payment code is however quite long, making it more difficult to share in person.
Fortunately, there is a directory of payment codes at https://PayNym.is .