I’m trying to raise my Hedonism above 8 but i cannot find out how to do it. It seems a lot of former methods have been capped at 4, including the laudunum. I want to increase Hedonism without losing nightmares as I want to become closest to Bohemians. Any advice on what to do?

I know that if you’re intimate with the devils, there’s an opportunity card (A quiet picnic) that can raise it to 10.

Also, during a visit to the Tomb-Colonies you can raise it up to 10 quite easily. You get there by having Scandal reach 8.

I haven’t personally encountered anything that raises it above 10. There’s a list on the wiki if you want to click through the options to find something you’d be able to do.

That list is out of date. It actually states that drinking the laudanum can raise it to 9, but it is actually capped at 4.

I’m using Concentrate on the Food and The Nibbles Tray through a Polite Invitation in Veilgarden to buff Hedonist to 10.

At Hunter’s Keep, repeat carousel and choose “The Three Graces?” at the end of it.

^ That’s usually how I do it.
In my experience Concentrate on the Food seems to give about 3CP (give-or-take - I’ve never done the exact math on it) of Hedonism, so what I tend to do if I want to max Hedonism is get it up to 10, the use the Attend a church fête on the south bank of the River option on the Altars and alms-houses: the Church opportunity card to reduce my Hedonism down from 10 into the top edge of Hedonist 9, then Concentrate on the Food once more to max it out as much as possible. :-p
(I still have no idea if its even possible to raise above 10, including via Fate, so I haven’t tried.)

Giving Romantic Notions on the Mr Wines is holding a sale card will take Hedonism to 10.

The only problem with Concentrate on the Food is that it reduced Nightmares. I need to keep my nightmares at 6. Maybe I’ll be off to Hunter’s Keep then… Accepting the Devil’s invitations seems to help as well.

Hunter’s Keep can reduce your nightmares. I know there is an autofire reduction if they are high enough and some of the storylets also reduce them.

Laudanum can still increase it to 10, but you have to develop a significant addiction to the stuff, to the point where you are in fact doing it more for the Hedonist than for the Nightmares.

Consider that you can easily increase Nightmares by Seeking Curios in the Forgotten Quarter, though, even at max stats.