This porn video tag refers to a specific category of adult content involving individuals with both male and female physical characteristics. "Shemale" is often used as an umbrella term for transgender or gender non-conforming individuals who have both male and female physical traits. In this context, the focus is on their male genitalia, specifically their penises.
The phrase "nice cocks" implies that the shemales featured in this content possess particularly attractive or well-endowed penises. Therefore, the overall tag suggests a video featuring transgender individuals with appealing male genitalia. This content may be of interest to those who appreciate transgender pornography and find such physical attributes visually stimulating.