I've heard of people doing this on another forum. One issue is the fact you can only absorb a tiny amount at a time when snorting a supplement. Another issue is the fact that formestane is not very water soluble, and the membranes through which you're body absorbs compounds via insufflation are hydrophyllic, so you're still not going to get a very good absorption rate.
From what I've read, intranasal/sublingual steroids are crappy because they need to be taken in a cyclodextrin solution (to get a reputable absorption rate), and need to be taken way too frequently to obtain a desired dosage. Therefore, they are most typically used as a pre-workout stimulant, and nothing more. Formestane, being a prohormone of a relatively weak steroid, and typically only used because of its aromatase-inhibiting capabilities would not strike me as something that's worth the effort of going through all of this.