Wasabi, as I understand it, is horseradish, probably prepared with vinegar, and certainly green coloring.
Even the tiniest trace on one's toothbrush would be intolerably hot!
Sushi rolls are often made with sticky rice which seems to hide some of the heat of a bit of Wasabi, depending on which hits the tongue first. Although we may not be able to avoid the sinus-cleansing fumes.
I'd suggest that anyone wanting to try this begin by mixing less than a pea-sized bit of Wasabi into a large bowl of cooked sticky rice, and using that mixture to clean the mouth.
Of course, in the Bahamas SOME love Goat Pepper, so much so that they shake it on everything. I'm told that Goat Pepper is pure heat; no flavor. A bottle of the yellow preparation is often found with the table salt and black pepper on tables in Bahamian restaurants.
I didn't see anyone use it, in a year of living there.