Margaritas, anyone?

Jessica Simpson — looking slimmed-down and sexy — works on her tan poolside in Mexico on Thursday.

Jess was joined on her vacation by some girlfriends, and even her mom Tina came along.

At one point, when Jessica’s girlfriends saw paps snapping her picture, they tried covering her up to protect her. (Photo: Flynet)

Click here to see more sexy photos from Jessica’s Mexican vacation.