You might want to update your Journal and add a rule like: "Please try to alternate between cute and naughty art. If you already asked me to draw a naughty picture and I drew it for you, try to ask me to draw a cute one next time you make a request." I hope I'm not bothering you, I just think it's a good rule so certain people don't try to make you draw too many naughty things all at once.
I had a similar problem when I took requests, except people kept asking me to draw characters from little kid's shows alot(like Dora the Explorer and Blue's Clues), not that I find anything wrong with drawing those kind of characters, but I also wanted to draw other things too. I'm definitely going to make that rule when I reopen requests, hopefully someone will understand.