Button Mash asks Sweetie Belle if she can give him a glowjob before bedtime, but the young filly has trouble using her magic in such a way.

Unable to see her sister in such despair, Rarity steps up to perform her duty as a big sister!

Inspired by an image created by Ohohokapi. Sorry I can't link to the specific one but that is apparantly against the rules. If you turn off explicit filters though you'll recognize it from the (poorly) edited cover art