It happens I have an extremely goofy dog. Teasing him as he thrust his legs in the air as if doing some high hurdle in reverse lying on his back on the couch, he looked over upside down and winked at me. He probably thinks me goofy as I exercise horrid approximations of yoga postures.

It became suddenly clear that a wink is a gesture of trust. I winked back. He winked again…

This is not my dog, but you get the idea. Seems likely to mean, ” I can take my eyes off you, for you are my friend.” Of course, humans can construe anything and we can spin winks cynically, but that is our problem. Dogs just don’t do that.