when a waiter at a restaurant feels the people in his section are ass holes the waiter dips his penis in to the guests water until his penis starts to turn blue from the cold the the waiter serves the water to the guest and watches them take the first sip
This refers to the process where a DJ is building up to 'Dropping the Bass' in their mix while performing at a nightclub, but then doesn't follow through, and leaves the entire dance floor feeling thoroughly unhappy and unsatisfied.
Guy: "Oh, here it comes! He's about to drop the ....Eeargh! No! that DJ just gave me Nightclub Blue Balls !...My night is ruined"