This. Absolutely. (This is my coveted, much practiced deep throat secret! But I see the secret is out! lol)
Seriously, it sounds odd and feels odd with an empty mouth...but add some thick spit and a nice wide cock and you can feel your throat open as you ease it down deep.
(Sorry, I meant to reply to achilles1's post...."Had a girlfriend in college who showed me how she relaxed her throat muscles by just kind of jutting her lower jaw a little once she felt the head almost reach the back of her throat. When she first showed me we were just talking and it looked kind of silly but later she showed me how it helped in practice and it did seem to help her. Needless to say I was just glad to be the one she practiced on. She also said that sometimes its better to switch around like u r in 69 position depending on the equipment of the guy.)