I dropped down to a 4 day week so that I could look after my son one day a week. The negotiations were pretty simple, I just told my boss that due to our circumstances I needed to drop down to 4 days, and his reaction was basically I’d rather have you working for 4 days than to see you have to quit ( I never even mentioned quitting, but I guess I put it in a way that my circumstances didn’t give me much wriggle room).
And honestly it’s the best thing ever. I get a whole day each week where my son and I get to explore and play and have fun together. He’s 15 months old and he’s never going to be this young again. I’m super grateful to my work giving me the flexibility, and I enjoy work more than ever before because I get to have a better life balance.