For myself I don't ever feed seconds so there is never a need to ask. I know what the kids will eat and that is the portion they get. There is no negotiating on what part they will eat or how much. They eat what is put in front of them.

I would not remove him from the table. As hard as it is to hear him scream I wouldn't go through the extra work. Squeeze his hand (just enough to get his attention) and tell him firmly NO we do not scream at the table.