General

Wow, I'm jealous, never thought of it before, but would love a feederism date (both ways!) one day.

Anyway, best advise I can think of is to make sure you're hungry and feel gluttonous. Being a little horny will probably help, so don't masturbate for a day or two

Make many trips up to the buffet tables. Avoid veggies or healthy fare. Show him you're serious about getting your money's worth and you're not gonna stop just because you feel full.

Choose hearty, fattening items and make sure to savor them. After several plates, pause to rub your belly now and then. Be sure to pace yourself.

Most of all be receptive to his likes and suggestions. This is sure to become a habit and you'll enjoy it more every time!