1 - don't use 100% PG juices. 100% PG lets through nicotine's skin irritation the best. I recommend 80PG/20VG or even 90PG/10VG would help. If you are using atomizers, you could use 30% VG or more, tanks 30% or less, stuffing cartos I like 20% or less (VG makes juices thicker and some methods of vaping don't like thick.)
2 - Use cartomizers like Boge 3 ohm (slim 510 can use 2.5 to 3 ohm) and put a simple plastic or delrin drip tip on the end of the cartomizer instead of the endcap. The wider hole in the drip tip brings in a more diffused wider stream of vapor and the shape of the drip tip should bring the vapor in at a different place.
3 - clean your stuff - if there is congealed liquid stuck in the end of a drip tip or on the end of a cartridge, that is continuous irritation. And with cartomizers, if you don't clean up overfilling and loose liquid well, then that liquid will end up being shot as hot little droplets right at the tip of your tongue, causing blisters.
The brief version of how I fill and clean up cartomizers
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The carto has a 1ml capacity. You need to aim towards putting 1ml in. I hold a tissue on the threaded end hole, tilt the carto and drip in 18 drops (waiting longer for the first few to soak in), Then I wait 15 seconds. Then I see how many more it will soak in easily (usually 3-6, occasionally more). Then I clean it up - clean threaded end, tilt open end down into tissue and puff into threaded end to clear the air channel, then while still pointed down I just touch a soft bit of tissue to the top of the stuffing to sop up excess (to help prevent leaks). Then I let the carto settle. I use juices with 20% or less VG so 15-20 minutes of laying it on different sides is plenty of time for every bit of stuffing to get damp.
While vaping - any time the vapor seems light, dry, or tastes the tiniest bit off or loses flavor, or if the caro is getting abnormally warm, I add liquid. I also occasionally look at the stuffing (especially before putting a fresh battery on or before going out) and if the top of the stuffing looks white, I add some juice. No settle needed when just keeping the carto damp. And if you do not keep it damp or if you use juice that is too thick (too much VG) you will singe the carto and that adds a bitter taste. I use a simple plastic or delrin drip tip in place of the end cap so it is easy for me to remove that to look at the stuffing or add juice.