It's very simple.
You just follow this account, it follows you back and you're done - the folks on Mastodon (or any account on the Fediverse) will then be able to see your post too!
@ap.brid.gy
RE: https://bsky.app/profile/did:plc:65ovld2hwba43z7y22pxgssf/post/3lrh4tps3zew2
If you have a fediverse account, you can quote this note from your own instance. Search https://bsky.brid.gy/convert/ap/at://did:plc:6dogihoiskbz3flxsifm22eq/app.bsky.feed.post/3lrh55en5jh2j on your instance and quote it. (Note that quoting is not supported in Mastodon.)