Of all the characters to tattoo onto your arm, this is probably the "safest" (not to imply there's any shame in admitting you love ponies; real men wear pink). In an awkward scenario, you can say it's a shapeshifting succubus-type demon thing and be telling the complete truth without even saying the word "pony"

Covering your arm in a creature that needs love to live?
…
There's a masturbation joke in there somewhere…