It is something you should know. And it's scary because you can kill a calf if you get the liquid (colostrum replacer/supplement, milk replacer, electrolytes) in the lungs. My vet walked me through it the first time.
There are numerous esophageal feeders available, but my favorite (by far!) is the Trusti Tuber. It makes drenching a calf virtually foolproof. I even bought one for my vet a couple years ago (he also has cattle) and now, that's all he'll use. The length of the tube can be adjusted according to the weight of the calf. The calf clamps on to the mouthpiece or there is a clip you can attach to secure it to its mouth, and you simply slide in the tube. The bottle has a vent, so no awkward squeezing, and also comes with a nipple similar to the peach teat.