I definitely choose R18+ drama cds lol
Not all of them focus on bed scenes, there are R18 drama cds that are well-written and have heartbreaking, deep stories too. But they're darker and more immoral, which isn't something all-ages drama cds can get away with. There's no censorship, no 'fade to black' when things get too suggestive.
Some don't even have a happy ending, it's more like... a tragic ending. This kind of R18+ drama cd is rare, but most of them are part of a series.