This sign represents attaching a poster or a flyer to a bulletin board.
Press thumb tacks into the top two corners of a poster on a
bulletin board, then press in thumb tacks on the bottom two corners.
POST:
Sample sentence:
Do you post your phone number in the bathroom?
Notes:
You can use the sign POST to mean "bulletin board" by signing POST and then drawing a big square in the air with
both index fingers starting at the top middle moving to the sides, then down,
then back to the middle.