Step 1: "Social feeding" is a vague, non-technical phrase, ruled out.
Step 2: "Preoral feeding" means external pre-ingestion digestion, unrelated to sharing.
Step 3: "Proctodaeal feeding" is only one sub-type (anus-to-mouth), too narrow.
Step 4: The general term for mutual food exchange in social insects is Trophallaxis.