Here is a relatively "famous" video of a tankslapper
The bike develops an oscillation due to an event that upsets the suspension and straight line stability. It can be a bump, it can be extreme accelaration, it can be high speed with poor areodynamics on a heavily laden bike, it can be a sudden loss of traction of one end of the bike, it can be setting down hard from a wheelie, (taking your hands off the wheel while decelarating?), usually it is a combination of things. The only pivot spot for the bike to oscillate around is the front steering. In the video above you are watching a professional, someone who makes a living riding at 9/10ths+. He is helpless to get the bike back under control, he is not the one moving the front wheel side to side. Watch closesly and the point of the triple tree is moving in a straight line, it's the rest of the bike that is all over the road.
It is possible to ride out a tankslapper, the bike really wants to go straight, the oscillation will eventually end. You will probably however go down, not because of your riding skill but because physics and traction are at odds in the middle of the event. The bike is moving around the pivot point, the front tire is doing the opposite of the rear trying to work itself straight, traction of the tires now work against you and can actually make the oscillation worse.
The steering stabilizer basically eliminates the pivot point at speed, if an oscillation starts it dampens it.. like a shock absorber attached to both sides of your handlebars.
What you experienced was probably not a tankslapper unless you were scared shitless, crying, seriously considering never riding again and perhaps lost control of your bowels. You probably lightened up the front end considerably by pinning the throttle and the wind moved the bike from one side to the other. The strom is relatively light and tall and the wind affects it more than smaller heavier bikes.
I encourage you to slowly explore your limits and your bike limits, invest in quality riding gear, take a msf course, do not take the bike to the strip bar and chill out on the bike, enjoy it and ride it, learn!