Tread your rope through the sling. Be sure to back up your new thread with an ice screw while you test the anchor or the first person is rapping. Smile and toss back another cold one. You're an ice master!

Food For Thought: My personal experience is that ice is less strong when it has holes or pick placements that line up horizontally. I believe this is one origin of the standard advice to stagger your ice tools while climbing. So I try to stagger one v-thread hole above the next. This is not currently orthodox, so you might want to wait until more thorough tests are done before trying it this way.