Normally, Jedi do not really care all that much about each others outer appearance, as long as they do stay healthy and don't stink like a bantha, everythings fine.
Same usually goes for Obi Wan - but definetely not when concerning Anakin!

Anakin somehow decided that he wanted to get his skin inked, and now he has a huge ass tattoo all over his sexy, muscular back, or maybe something more laszive on his hipbone - it's up to you!
I personally would prefer him having his back and maybe even a part of his neck tatted.

Afer finding out, Obi Wan is super pissed, so Anakin decides to let his old master explore the beauty of this artwork that his body is - naked ;)

Whether there is anymore sexual action between them or just a lots of sexual tension and Obi Wan praising Anakin's godlike body, i don't really care and believe whoever decides to fill this prompt knows what he's doing :)


P.S: I also don't really know what motiv Anakin could want to have on his back forever XD