The Brief: Right in the feels means "emotionally impactful."

DEEP DIVE
If something hits someone right in the feels, then it packs an emotional punch. Such instances usually occur when something is relatable on a deep level. Whereas phrases such as big mood or that feeling when are a bit tongue-in-cheek, right in the feels is reserved for more somber or genuine occasions.
When Khalid says "maybe you weren't the one for me but deep down I wanted you to be" hits me right in the feels..
— Instant Turn Ons™ (@InstantTurnOn) February 16, 2019
This song hits right in the feels!
🎶💔 pic.twitter.com/E9gVR6CCEx— Vicky Luminiq (@VLuminiq) February 12, 2019