Take a breath and try to swallow the cock right to the root, pressing your mouth hard onto his body, continuing to try to swallow it. Actively swallowing will suppress the gag reflex and let you go right down to the root. Nibble away gently at the root of the penis, continuing to swallow using your throat to pull on the penis. The skill then can be used without the drug. With skill, you can even swallow 11 inches if you get your head angle right.
Some guys have a natural bend to their cocks.
Attack from an angle so the bend fits the natural curve of your throat. For inspiration, note the fascination the public has with sword swallowers. You might even read up on their techniques. Enjoy the feel of the penis with your tongue. Get into how pleasant it feels and tastes.