Not sure about a "Milking Table," But every Massage Table I've been on has had a removable pad covering a hole at waist level.
Always wanted to but haven't found one around here. Might be a lot of fun although I do like to watch and touch so it may not be ideal for me.
On Amazon.com for $289.00 Milking Table with Big Glory Hole The Milker: Classic - Massage Table with Glory Hole for Men - BDSM Furniture
Not my "cup-o-tea" as I prefer to look the person in the eyes while sucking my cock and prefer to caress his ass cheeks while looking up at him with his cock in my mouth.