Need fantasy ideas

My husband is really into dirty stories. The dirtier the better. The problem is that they need to be increasingly dirty, and I just don't have an imagination to keep up. We've been together 14 years, so it's hard to come up with new material.

So, I need ideas.

For reference, yes we have acted out many a fantasy. We are swingers, we flash, we flirt, we have actually done a lot of what most people only fantasize about.

Roleplay doesn't cut it. I can only explain it as a dear penthouse letters situation. He wants/needs the story during most sexual activities.

Thank you for any ideas