So I thought maybe allow_autonomous=true simply wasn't doing anything, or maybe I had the wrong set of files. They'll stand there and do plenty of autonomous flirts and embraces and other lower-level romantic interactions, but not woohoo on the bed. I have yet to have my test sims initiate bed woohoo by themselves, despite both of them being in a very flirty mood, with all their needs at 100% and need decay turned off, their romance bar filled to the max. There were separate files for bed woohoo, observatory woohoo, and rocketship woohoo.
To find the relevant files, I first searched for the term 'woohoo' in my folder of exported XMLs, then within that pile searched for the term 'allow_autonomous,' then changed the falses to trues. The first part was easy but I'm struggling with the second. Today I worked on figuring out a way to get risky and autonomous woohoo. I admit I'm new to modding, but I've been looking around in the Sims 4 XML files the past few days, trying to learn more about how the game works.