I am calling it smoking, "vaping" is a euphemism that just recently entered the language in an effort to rebrand the action of smoking because being "a smoker" now has a negative connotation. "Smoking" has never been a literal description of that action - the literal description is "inhaling tobacco" which is still occurring. The fact that using e-cigarettes is viewed as a more healthy way for smokers to continue their habit sort of puts the nail in the coffin in terms of word meanings.