Rihanna's Controversy Tattoo.... What a Sight?

Rihanna gave a shout-out to her tattoo artist on Twitter and Instagram. He is responsible for most of her amazing body art. He recently tattooed a friend of RiRi’s and she posted to celebrate.

I actually don't know the verse implications of the 2nd finger from the left cos i hope it's not what i think it is...
But my question is Why put a Tatto on your Finger?
GOSH!