I really like his little blush, paired with the rather "sad/humble" expression and the statement "drinking alone", meaning he probably has been or is still going through tough times.

Could be that the mouse girl was "paid" to do this to his paws. Or she just did it voluntarily because she enjoys it. I like to believe it's the latter.

Her eyes show some worry as much as they show desire. Maybe she's working in the bar or club and noticed he was always coming alone and never really talked to anyone. And maybe she secretly admires him, wanting to get to know him better, eventually leading him to a backroom, unclear if it was for sex or for something rather uncommon and purposeful.

That's what I interpreted in this picture. Love it~