I've been poly since my 20s, I'm 29 now

I experienced something strange today while at work. I was offered a chance at a poly relationship with kink elements in addition to the sexual elements of it.

Then the man started talking about various kinks he wanted to do to me. Then he said various penis jokes that I found highly inappropriate especially when you take into account I was at work. I've let my primary partner know about this incident but I'm still spooked.

How do I navigate this situation especially when they are regulars at my work. How do I approach with this type of situation with my primary?

I have discussed the collar thing with my partner, and he agrees that it'll be a good idea.

We are also a new relationship, and we are LDR and will be for quite a while due to circumstances beyond our control.

Please excuse formatting as I'm on mobile.