I'd pretty much suggest the same thing as everyone else: get a shoe box or a mailing box (having a box to store shit in is such a small thing, but once you have one, you wish you had more lol) and filling it with snacks based on what he likes.

I'd also suggest putting in a few photos (SFW) of yourself, and anything that he or both of you really love (pet dog, kids, car, honeymoon or wedding photo, footy team etc) and a small amount of blue tac so that he can stick these up in his bunk. If you have a favorite holiday destination or are making a plan to go somewhere, a nice photo of something to look forward to would also be nice.

It also seems like you are really open to some... Other things... Judging to your responses to porn and pocket pussies lol. If you really want to give him some personal wank bank material : get a couple of NSFW photos of yourself and laminate the photos... The only time your man will get some alone wank time will be in the shower or shitter... Help him out by laminating your NSFW stuff.

If your not comfortable leaving him with some NSFW photos of yourself (which will probably be shared with his best mates once or twice) just do the same thing with some porn stars or celebrities.

If you think he's into it, you can buy a set of thongs or sexy panties, masturbate in them, spray your fav perfume into them and zip lock bag it. He will no doubt find a good place to hide it among his kit. If your are sending him with some NSFW photos, make sure some of them include the panties your sending him and what you've done while wearing them...

Hope this helps.