perch on something
1. [for a bird] to stand at rest on something. A robin perched on the branch by my window. We saw a parrot perched on some kind of flowering tree.
2. to sit or balance on something. I can't perch on this fence forever. Let's go. Sam was perched on the bicycle and he looked very uncomfortable.
perch someone or something on something
to place, seat, or stand someone or something in a place. She perched the little girl on the edge of the tub. Walter perched his hat on the top shelf.