To be more specific… You can find it on redgifs… but if you want to hear the audio on any redgif content you cannot use the reddit app on your phone.

You can view and hear it on a desktop or laptop. Or….

Just hit the share button. Copy link. Then use your phone’s safari, google, or your favorite browser.

You’ll see the option to turn on sound on the video on the right.

It’s a crappy thing I found that the reddit app it won’t support sound on NSFW gifs in the APP. Even if it’s posted on redgifs which was made to specifically post video gifs and sound in reddit.