Clean out your chosen container and put the sugar in the bottom.
Add your prepared damsons then pour in the gin.
Give it a shake to mix the sugar in and then agitate it every day until all the sugar had dissolved. Then just agitate it every so often leaving it for at least three months.
After three months it is worth giving it a taste to see how it’s getting on. If it’s how you like it, drain the gin off and see notes below.
Notes
Once you have drained off the gin you can try adding more fresh gin and sugar to make another batch. Alternatively you can de-stone the damsons and use them for a pie or crumble.