A proposal from a cswiki mentor: He says that he tends to forget to mention the mentee, and that a button for replying can be useful. I can see why this can be useful for mentees as well - they can simply reply to the mentor and ask for any follow-up. It can look like this.
The buttons can display an overlay with a reply interface, or just prefill the wikitext one. The reply to mentor button will not mention any user, the reply to mentee will mention the mentee. Alternatively, we can let the system detect what should happen based on current mentor.