Headcanon that Hiraeth desperately wants to help Astarion improve his charisma. Give him rizz tips. His face and voice are perfect for non-sexual (or implied sexual but never actually fulfilled) honeypot tactics.

He's too self-conscious and prideful to be a performer, too tied up in his own myth, but he can become an expert swindler and con man with just a little bit of guidance.

And they are so so so desperate to offer that guidance. They wanna see him wreak absolute havoc without having to use his body. Teach him subtle, soft power that can benefit him without taking anything away from him.

Also they do just want an excuse to tell him he's completely rizzless.

Idk there's a post going around saying to multiclass him into Bard or give him Bard Initiate and I thought of it in story terms, of a bard teaching him how to bard. I think it's just really cute if they give him tips on how to properly use Vicious Mockery. I feel like he'd have fun insulting people so hard they're literally physically damaged by it. And because he's got that Charlatan background and is inspired by a lot of bard-flavored nonsense, I feel like he'd be into learning a bit more about how to manipulate people without having to sleep with them. Without having to sacrifice anything but a bit of your morals, which he's happy to do anyway. His body is priceless but his words are cheap, so those he'll throw at people no problem.

And Hiraeth just goes "Yeah! That's my guy!!! My sweet cheese my rotten soldier!!"

And after [redacted] they team up to scam people. Astarion in his fanciest most official-looking elf noble getup going "I have an excellent business opportunity. Yeah it's an expedition into the Underdark for newly discovered magic mushrooms that improve your virility. Yeah it's totally gonna take the world by storm. Proof? Well here's one of the adventurers going there. They're totally legit, as you can see. A real hero type. Let's listen to their very convincing story about the Underdark. Now, how much would you like to invest?"

Yanno? Ya picking up what I'm putting down?