foamily

With her other hand she was foamily scrubbing away at her teeth with my toothbrush and toothpaste.

A huge blue brush appeared out of nowhere and started foamily to scrub at the teeth, which continued to hang there gleaming in the shimmering curtain of rain.

There was a threshing rush, the waters stormed foamily, there was a glimpse of a blunted, reptilian snout, and the trailing body vanished with it.

I rejected foamily, which looks too much like "family" and sounds like a dialect rendition of formerly, as well as frothily, from the expression, less common in America, of "frothing at the mouth."