"Tranny-sucks-bbc" is a tag for a porn video involving transgender individuals. In this case, the term "tranny" is a colloquial and potentially offensive slang term for a transgender person, often used in adult content. Here's the breakdown of the tag:
1. Tranny - Transgender individual
2. Sucks - Oral sex performed on a penis
3. BBC - This abbreviation stands for "Big Black Cock", which refers to the large penis of a black person, or in some contexts, simply a black man with any size penis. It is used here to highlight that the person performing oral sex is transgender and receiving oral sex from a black individual with a large penis.
So, this tag indicates an adult video featuring a transgender person (tranny) engaging in oral sex with a black individual possessing a big penis (BBC). Note that these terms can be considered offensive or outdated by some people and communities.