‘Brolic ahh dih’ is a play on words, simply referring to not just a big dick, but a substantially strong, veiny, muscular dick (hence the use of the all encompassing synonm ‘brolic’).
The term/phrase (and others similar) were cultivated though out social media
meme pages, most commonly found on
memes targeting and ridiculing the transgender and queer ‘
son’ of basketball star Dwayne Wade. His child, Zaya Wade, would naturally be suspected to partake in homosexual activities, a commonly ridiculed activity, hence the
memes uprise.