On “Do Not Disturb,” two of Boston’s more promising up-and-coming rappers Black El and Michael Christmas team up to reflect, as the former puts it, “on what it’s like to be carefree and misunderstood at 19, from two different perspectives.”¬†Over producer Durkin’s woozy, El and Christmas trade pointed verses, providing the sort of concise, clever narrative that dots each emcee’s catalog. Another enjoyable listen in advance of El’s upcoming project¬†L_ST.