Let's play horsey!

You’re strong. Damn strong! Thanks to growing up with younger brothers and sisters, you learned some truly important skills. Carrying unconscious bodies no longer slows you down or makes your Dexterity (AC) checks and attacks harder. Even allies riding on your back—if their size is one category smaller than yours—don’t hinder your mighty strength. When one of you is attacked, you must try to defend with disadvantage on the attack roll, and only if the attack misses you does your sibling make the saving throw, but with advantage.