I want to make a raindrop fall..

I have this game were you are a cat. Cats hate water etc. I have a raindrop. I know how to make it fall, but i dont know how to make it go back to its original position fall again, repeat. How do i do that?

If you want that change its position by taking collision—number ( ? X 32 , 32 pixels is a full tile)–position (+Y)