1. I'm looking for fics where Sam takes care of a younger Dean.

What I've read -

• The Starting Over 'verse by iamstealthyone, which I loved, where in saving Dean's soul from Hell, he's reborn as an infant, and Sam raises him (+funny Bobby helping moments). - WIP
  
• Also Under a Haystack, which was good, but dealt more with Sam trying to change Dean back, than many daily moments of taking care of a child.
  
• Have Yourself a Merry Little Christmas was fun, with Dean de-aging to 4, but he kept his adult mind, and I'm looking for something a little more childlike.

2. In a similar theme, any fics where one or both of the boys de-age into babies/toddlers.

• Like the Starting Over 'verse above, where one brother's an infant and the other cares for them.
  
• Or Even as a baby, Dean's a total dog, where both Sam and Dean regress into infants, and Bobby and Ellen have look after the adorable twin terrors until they change back.