The phrase "friendly reminder" means a gentle and kind message to remind someone about something important or to encourage them to do a certain task. Full definition
Keep moving toward your goals with friendly reminders that encourage you to stay active throughout the day. (fitbit.com)
It's simple to navigate, and provides friendly reminders, inspirational messages and links to useful resources to make it as easy as possible for women to monitor their wellbeing. (rch.org.au)
These are likely things we've all heard or read before... but a little friendly reminder never hurts. (confessionsofadrmom.com)