...I dissolve my DXM powder in a few mL of DMSO (it dissolves easily at room temperature with half a minute or so of swirling), suck it up using one of those oral syringes you can get from pharmacies or pet shops to give medicine to your baby or pet, and squirt it into the back of my mouth. Wash down with whole milk, swallow. Drink some more milk to get the taste out.
Works great, I’ve had no nausea this way even with large amounts at once (500mg). Whereas a 300mg DXM powder gelcap (from the same batch of powder, I was just lazy and put it in a gelcap that time) gave me horrible nausea on the comeup probably from undissolved DXM sitting on my stomach lining or something. The key to avoiding nausea seems to be to keep it in solution in the stomach. DXM isn’t terribly water soluble and has a tendency to recrystallize from solution and such.