Getting sucked and fucking my straight neighbor (His first time)

My straight neighbor lives on the same floor, and his whole family lives in an apartment next to mine. We had never exchanged a word, and he was with a man for the first time. He is so straight that it never even crossed my mind that something could happen between him and another man, let alone me, who lives right next to me with his whole family. My apartment door was left open without me noticing, and there he was, standing 5 feet from my door, watching me naked on the couch.