It means to "Check In" // "Accept" the Battle in a certain time, or else it is Auotmatically closed if both do not do it withing the "Required" time..

Its time to drop homie, It was set for "One" day, drop your spit or else itll DQ you man, n it aint a good DQ for no reason, ill wait for you to reply before droppin since i don' want yo broke ass to get a DQ, ight, holla back...