How do I repoint an existing block wallcap that hangs off wall by 3" on both sides?

Question

There is no mortar in the joint, so I basically have a gap to repoint, with no bottom. What's the best method of getting the new mortar to stay while it dries?

Answer 1

if you are saying that there is nothing to push the new mud against , you can ask for backer rod at the hardware store and tuck that in the crack and tuck the mud against that...