I think that is a graphic art for the name of a Sushi place, which looks like "Longevity Official" since the second bottom character means Official, administrator. Administrator Kanji character
So the name of the sushi place is "Administrator of Long Life" or also "Officials of Congratulations" - a place to go after work for a promotion type thing.
FWIW, it looks like half of the symbol usually used for "sushi"
Unagi
full kanji for sushi = 寿司
Maybe the other side of the mug has the second character?
This pose was very deliberate. Is he flashing he likes sushi or Asian men?
Twitterverse seems to be creeped out by this photo.
Another reading for this kanji combination:
寿司 • (Hisashi) a male given name
This may be most likely: 寿 = shinjitai = congratulations or longevity
Congratulations on his new job?
Shinjitai, 寿, is often written on gift envelopes in Japan.
Maybe someone familiar with the Japanese for "congratulations" gave him the coffee mug as a gift.
司 Can mean "boss" or "manager"
If I show this mug to my husband, he will say, "That is shinjitai, congratulations."
I think that is a graphic art for the name of a Sushi place, which looks like "Longevity Official" since the second bottom character means Official, administrator. Administrator Kanji character
So the name of the sushi place is "Administrator of Long Life" or also "Officials of Congratulations" - a place to go after work for a promotion type thing.