I don't mean to be NSFW here, but traditionally this is a fisting tattoo... A lot of bears (of the big furry human sort) and the like are going to making assumptions.

Very cool... I made a very similar design of ring.... I like the way this one is done too but in mine I moved the lightning bolt inside the glasses so that it wouldn't get caught on things. I also did a similar ring based on the glasses that Spider Jerusalem wears in Transmetropolitan, and also made a skull ring wearing those glasses.... Had a lot of fun doing them.
PS. Here are images of what I'm talking about:
http://www.zentastic.com/blog/wp-content/uploads/2011/09/harry-potter-glasses-ring.jpg
http://www.zentastic.com/blog/wp-content/uploads/2011/12/transmetropolitan-ring-4.jpg
http://www.zentastic.com/blog/wp-content/uploads/2011/12/spider-jerusalem-skull-ring.jpg