To drape over s.t. (as a towel on a chair or clothes on a clothesline).
The pa- prefix is often used interchangeably with the -um- infix for marking unintentional action. The -an imp. focuses on the object that is being drapped over s.t. The -un imp. focuses on the object that is being drapped but it must be drapped over the one who is commanded to drape it. The pa--un imp. focuses on the object and the goal where the object is to be draped. However the pa--un and -an imp. can be used interchangeably when the goal is specified.
The coconut branch happened to get draped over that line (when it fell from the tree).
The reason I was terrified was because he draped that snake on my neck.
Drape that towel around your neck/over your shoulder.