RYO = roll your own cigarette
WTA = whole tobacco alkaloids. It's something Aroma makes, instead of just nicotine they do their own extraction starting from the tobacco leaves, it picks up a few more chemicals from the tobacco. Supposedly it can provide a bit more of a cig-like calming effect.
For some, just nic doesn't quite cut it, so they
supplement with either WTA or snus (the fancy Swedish stuff, not the same as classic american chewing tobacco -- snus is much healthier).
I'm a mutt, and
vaping nicotine alone is fine for me. I'm going to make some WTA DIY just for fun. I was thinking some high test, perhaps 30 mg/ml, tobacco, but probably also do some lower mg mix, open to suggestions. Probably split it into 10ml bottles to pass around.
Apparently the unflavored WTA is effective at about 25% in a mix, and at least some people use it just as a supplement, those couple of "gotta smoke" times in a day, vape normal nic eliquid the rest of the time.