"Trap-ass" is a slang term in the context of adult content, particularly in hip-hop culture. The term is derived from the word "trap," which generally refers to a place where drugs are sold or used (i.e., a drug house or street corner). In recent years, it has evolved into a more general term for describing an attractive female behind, often used as part of other phrases.
In the context of adult content, "trap-ass" could be interpreted as referring to a woman with a particularly voluptuous and shapely derrière, possibly implying that she may have undergone buttock enhancement procedures or uses specific techniques to accentuate her curves. This tag is meant for audiences who appreciate the aesthetic of a full, round behind in adult content.