I don't get it. Pure Tung oil is a fantastic finish, but nearly every article I read and even the product directions make what I think is a mistake. That mistake leads to failed finishes and disgruntled woodworkers.
Bad advice #1: Flood the Tung oil on the wood
The recommendation I see in articles AND the product directions are to thoroughly flood the wood with thinned tung oil until it will drink no more. Then wait 3-5 days for it to cure before adding more coats.
Tung oil is a drying oil and cures due to polymerization with oxygen. Flooding the workpiece with Tung oil only insures that you fill the fibers with so much oil that will never see the light of day and will take years to cure internally. Tung oil cures at the boundary of oil and air. So the surface that contacts the air, will skim over leaving the oil trapped beneath starved for oxygen. Contrary to popular opinion, the wood is not nourished by oil, nor does it have a thirst that needs to be quenched. Trapping oil super deep in the wood is nothing but heartache waiting to emerge.
My suggestion is put on a decent coat, no flooding, then give it time to cure WELL. Give it at least 7 days. When the rag you put it on with is hard and crusty, it is cured. When the first coat is cured, the wood will not soak up as much oil on the second coat. If you just keep putting more oil on without giving it time to cure, the wood will appear to keep drinking it in, because it is. It is drinking it in and adding it to the reservoir of uncured Tung oil lying beneath. Each successive coat should be light.
Bad advice #2: Keep it out of the sunlight
Many articles suggest keeping Tung oil out of the sun because it causes it to cure more rapidly, then bemoan that Tung oil takes so long to cure. The truth is that UV light causes Tung oil to cure ~30x more rapidly. Yes if you slather the wood with Tung oil and you put it out in the sun, you will get a wrinkled tacky mess. However, if you put on a really light coat and wipe it off as completely as possible, then put it in the sun, you will have a nice finish that will be ready for another coat the next day.
Source article with more details: What most articles get wrong about Tung oil