Where a male sasly takes the brother approach, whilst strategically planting the seeds of love in the otherwise oblivious "sister" victim, and allows 14 years to pass before finally reaping the produce of a perfectly sown seed.
i think hes on a bro-sis ting bruv, you no say hes on it
a sister (usually biological) who is also a bro, displaying all or some of the characteristics of a bro.
Not to be confused with brosis which is an infectious disease.
My sister is totally a bro-sis.
Last night my bro-sis had a party at which she wore a polo shirt, drank beer from a red plastic cup, and shouted "WHOOOO" loudly several times.