How do you tell a friend his gf is annoying as shit?

Unfortunately you can't :|

no you don't

Tell directly

Maybe do a constructive criticism, a compliment sandwich.
She's pretty
She's very annoying
I'm happy for you/something else good

yeah, sorry.... that's a no.... bro's before ho's is a myth.

You don't. It's impolite

You don't. 😂😂

You really can't if you want to keep the friendship.

Be HONEST and say ffs your girlfriend is as annoying as a turd in a swimming pool in summer

A good friend? If so then suck it up and be happy for your friend that he has a girlfriend...
You can always ask him what he sees in her. If you see what he sees then maybe she becomes less annoying...?

You dont...

you dont, the vagina is mightier than your word. just be there for him when he works it out and dumps her

"hey, your girlfriend is annoying as shit"