Quick Definition: A pause or break in the flow of an interaction.
Stalling is when a PUA is in set and the conversation hits a lull or an uncomfortable silence. Stalling can happen for many reasons. One common reason, especially with a group of strangers, is that the PUA has not made his intentions clear or has not used a false time constraint to make it clear that he will not take up too much of their time. This can create an uncomfortable situation, where the set wonders what the PUA wants from them and when he will go away.
Conversations also have natural pauses, so a PUA should not immediately eject just because the conversations stalls or he temporarily runs out of things to say. The best thing to do in this case is to relax for a minute, then stack forward with another routine, or ask another open ended question, especially if the conversation was going really well before it stalled.
Many GPUAs tend to eject from sets too early, but by staying in set—even if it’s a little uncomfortable—they can push their comfort zone, improve their recovery skills, and have a chance of getting a close.