"Buttcrush" is a term used in the context of adult videos and it refers to a specific fetish or kink involving intense pressure being applied to someone's buttocks. This can be done with various objects like pillows, large balls, or other props that provide compression or squeeze the person's bottom. The tag may also be associated with a dominant-submissive relationship dynamic where one partner enjoys having their buttocks compressed or squeezed by another person. It's important to remember that this tag is intended for adult audiences who are familiar with and consenting to such activities.