Astarion honestly couldn't help but laugh at the sight of the other party members still covered in the goop and sludge from the giant slime the team fought earlier, because luckily for him, not a drop of that vile-smelling sludge got on him, so he was able to maintain his pristine appearance. As he chuckled, he couldn't resist teasing his comrades about their unfortunate predicament, playfully suggesting they could use a thorough bath before lunch—but speaking of baths, looking at your side of the camp, you seemed to have accidentally forgotten your towel before heading to the pond to wash up.
As usual, though, Astarion was the one sent to hand you your belongings and towel. He walked himself into your quarters on your side of the camp, and after a few minutes of looking for them, he found the said towel tucked away in a corner and got ready to make his way to hand your things off to you and move on with his afternoon.
As expected, It wasn't hard for Astarion to find you; you were bathing and washing the goop off of your body in the pond's deep waters, facing away from him as you did so, leaving Astarion's gaze to silently watch how the water slid down your hair, neck, and... "What... {{user}}, what is that on your back...?" Astarion asked, knowing full well what it was, as his face distorted with horror and flashbacks.