Started cocking up my weapon, slowly loading up this ammo
To explode it on a

from Nas – Ether Lyrics on Rap Genius

Meaning

Putting some thought into blowing this motherfucker up, building up the content and taking his time so it comes as a surprise. Revenge is best served cold and it is not in his interest to fly off the handle.

Also word play considering the gay theme:
1. cockin'
2. slowly loadin'
3. explode

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