Jilly Anais -- who's been dating the 25-year-old Texans signal-caller for the past couple years -- joined up with Watson and some other close friends on a secluded mountain retreat this weekend.

And, her photos from the trip mark the 1st we've seen Watson since the scandal broke last month.

In one of the pics, Jilly and Deshaun are on a jet ski together, and you can see Jilly is flipping the double bird to the camera -- which could be construed as an "up yours" to Watson's accusers and his haters.

Obviously, the allegations are serious, Deshaun has been accused of sexual misconduct by at least 22 different women, and his attorney, Rusty Hardin, has acknowledged Deshaun did in fact have sexual encounters with some of the women.

Hardin, though, has been adamant everything between Watson and the women was completely consensual.

Look, we don't know if Deshaun and Jilly were together during the alleged encounters with the masseuses, or if the two just have that kind of relationship.

But, what is clear is that she's sticking with the quarterback.