I used
gwasi.com to type in "multiple" + "milf" or "mom" or "older woman" search terms. You can see the "multiple orgasms" tag is commonly used or sometimes "multiple loads" or something similar, but there isn't going to be a commonly used "two orgasms" tag. I also used "score:>400" to filter out results that don't have at least 400 upvotes, you can raise to like 900 or whatever. Just FYI if you want to find more.
The last audio link on this list isn't on reddit though, it is a kemono.su link. You can find audios there in a similar way, it just isn't as quick and easy. Kemono has exclusive audios though..
Search "F4M MILF" for example, and the results will mostly be audios because only audio performers use "F4M" there (it only means female voice for male listener).