The Perks of Being a Jailbird is a secondary quest in the Blood and Wine expansion. It is only available during Burlap is the New Stripe quest and must be completed during the same quest or else it will fail, as you'll no longer have access to the prison.
This quest is only available if Geralt was sent to prison, which can only happen if Syanna was killed. After Burlap is the New Stripe starts and you finish talking to Handsome Jacques in the prison yard, look at the wall that was to your back when talking to Jacques. You will see a brick in the wall that you can interact with, which then gives you the note, Notes found in the Toussaint prison. Read it to learn another inmate is looking for a hammer and chisel.
To get the items, head over to the wagon underneath the gallows and loot it. Then simply go back to the brick and place the hammer and chisel in it. Now, you can either choose to meditate ahead 7 days or continue the main quest. At a certain point, a week will automatically go by and you'll be let go. As the guard leads you to freedom, head over to the brick again to retrieve your reward and complete the quest.
- One could put forward the brashly contrarian thesis that a stay in a prison would be a welcome change for a witcher. I know, I know, but bear with me: remember, a witcher spends his entire life, or at least a good part of it, wandering around trackless wildernesses and sleeping with no shelter but a hedgerow or a few bare branches. Therefore, a penal institution, which by definition will have walls, and most likely a roof as well, will at least protect him from strong winds, unexpected morning rains and the droppings of passing birds. Ergo, it would present an upgrade in terms of comfort... though at the price of a downgrade in terms of freedom.
- While becoming intimately acquainted with the charms of prison life, Geralt found a secret stash, used by inmates for purposes of trade.
- If Geralt hides the hammer and chisel, then checks back after 7 days:
- The witcher puzzled out what to do to use the stash to make a trade. A certain fellow inmate greatly desired a hammer and chisel, having had enough of the prison's hospitality and wishing to take his leave of the establishment. Geralt placed these objects in the stash, and in return received... a placard.
- A very interesting placard, in fact. An object of great desire in its own right.
- If Geralt decides not to wait the 7 days:
- Geralt decided he did not care to check how much a hammer and chisel could fetch in prison currency.
- Read the notes.
- Search for a hammer and chisel.
- Hide the hammer and chisel in the stash.
- Wait seven days.
- Check the prison stash.
- The name of the quest is possibly in reference to the coming-of-age novel, The Perks of Being a Wallflower.