I have asked a number of people and have been advised, that 'Lucky Bastard' does not translate directly.
There are a number of option you could use -
“Tá an t-ádh dearg leis anamadán sin”.
There is no word in Irish for 'bastard', so you would have to use the word 'eejit', which translates to amadán.
As said, there is not really a direct translation of “Lucky Bastard” in Irish. Although, if you wanted to instead get “Jammy Bastard”, it would be: “tá ant-ádh dearg ort!”
I hope this helps and good luck. And don't forget to add a picture of the tattoo to your post, once you got it done.