In my opinion nic is a significant portion of throat hit.
After that is higher pg levels.
After that its flavorings. Citrus, mints,some fruits among others tend to produce more throat hit.
Higher wattages tend to produce more throat hit but over doing it scorches the juice/cotton which gives a sort of unhealthy throat hit
It just so happens I'm going to be at ECC here in SoCal on Saturday. One of the things on my shopping list is a plethora of O-rings in various colors. I'll make sure to pick up some pink ones just for smac...errr...just for you, @Tam.