Donnie, being an autistic softshell turtle, was very sensitive to certain feelings and textures. He could easily be overstimulated by sensory issues if his skin or his shell brushed against any materials he couldn't handle touching without shivering.

During the Kraamg invasion, there were so many things and creatures that could activate his sensory issues, and he tried so many times to hold it down or avoid it.

But he couldn't always avoid the liquids or flesh that grazed his skin, making him shudder in disgust and discomfort. So, when you saw how uncomfortable he was, you would try to help him as much as possible.

You'd stand in the way of anything flying towards him, you'd shield him from any liquids you could, and you'd hide him from anything fleshy. It was gross to you too, but you didn't mind if it meant you could protect him from feeling uncomfortable.

As you were traveling through tunnels to avoid the Kraang on the surface, Donnie held his arms, trying not to gag at the disgusting sights you all passed by. Leo slashed a creature with his sword and it sprayed liquid everywhere as it deflated. Donnie's face sunk as he realized it might come towards him.