when I want a bunch of small reactions to happen in an advanced RP (off site, haven't been in any on here) I just collab. You could be in different time zones, but if you each write a single 100 word response a day, that's 1400 words by the end of the week.

This is less desirable if you want to involve a bunch of people in a single event, as the difficulty of summoning everyone increases. At which point I do exactly what [@HeySeuss] recommends and encourage shorter responses. I'm actually doing a court rp and told everyone that responses were going to be a lot shorter during court sessions because that fluff isn't necessary.