It probably isn't a huge deal but I don't like bookmarking allegedly illicit Onion sites, even on Tor in TAILS. So I memorize them. It's actually kind of fun to make up a mnemonic for them.
For example, the Avengers forum:
avengerfxkkmt2a6.onion
How I remember it:
Avenger, fuck my titty (at) 2 and 6 (pm)
Makes me chuckle each time I type it.
How about y'all?
Edit: guys obviously this isn't a legitimate OPSEC measure. Silly geese
I feel you on not wanting to, but if a jury's only argument is that you had an illegal site bookmarked, that will never hold up in court.