Do you have an option that says just "Mentor". Sometimes, the option does not show up on the first menu and you have to click More Choices one or two time to find it. For the instruments and pretty much anything else other than Acting, that is the option you need to use. And to be able to Mentor a skill, the sim must be level 10 in the skill.
Hope this helps.
No. Only Mentor acting. I did it exactly as it's supposed to work. I hired a stranger to play piano at a party and tried mentoring them. Then as I mentioned in my post, I added them to the household and maxed our friendship.
(CM: Multiple posts merged. Check out this post for tips on how to edit and add more to a post.)
Did a quick test and it does show up for me
Had my Sim play the guitar (the one with low skill) and then clicked on her with my high skill Sim and go the option
@PuppyofJam Hello! I agree with @crinrict here. The sim who is learning must be practicing / playing the instrument. Then make the mentor sim active (click on the mentor sim thumbnail) and click on the learning sim to get the mentor option.
In this image the sim on the left is the active sim and the sim on the right is the one learning violin. The menu shows the active sim's options when clicking on the sim practicing violin.
