To bang or bump into s.t.
[The -un imp. focuses on the object that is being banged into. The -an imp. focuses on the ogject that is being banged into s.t. else. The pagsi--un/pag--un imp. focuses on both objects that are being banged together.
I'll wrap a rag around my jars so they won't break even if they bang into each other.
If they don't obey, bang their heads together.