i filed an issue for BetterTwitFix to support iframely, and the developer implemented it. it appears to work perfectly. i've filed a similar one for FxTwitter.
to embed an nsfw tweet, or any other tweet which exists but won't embed normally, just place the URL on its own line like you would for other embeddable things, but replace "twitter.com" or "x.com" in the URL with "vxtwitter.com."
I'm not gonna demonstrate it. you can go try it for yourself. go hog wild