When I apply castor oil to the scalp (which is not so often since I'm lazy and happy with my hair length now), I do a mix of either 50 castor and 50 coconut OR 30 castor, 35 coconut, 35 avocado. If my scalp is feeling dry I'll use a lot of the 30-35-35 and massage it in gently. Doesn't seem to cause any hair loss but it's a gentle massage. When I was just trying it out for hair growth purposes I used the 50 castor, 50 coconut oil mixture and I tried aqua_lily's routine. She dips her fingers in until they're slightly shiny and just lightly dabs at her scalp all around. A miniscule amount. So modest she doesn't even have to wash her hair afterwards. (It's a nightly routine for her and she has hip length 3A curls.) It could be the oil just added slip to hair that was already trapped between your curls and waiting to come out upon detangling. Or it could be you massaged too vigorously upon application?
3A - C, HP, ME, HD. (Coarse, High Porosity, Medium Elasticity, High Density.)

CG since Nov. 2012

Poos: SM Moisture Retention + Yucca Baobab, TJ's Tea Tree Tingle
Condish: TJ 'sTea Tree Tingle*, SM Moisture Retention* + Curl & Shine + Yucca Baobab, Yes to Blueberries
Stylers: KCKT*, SM Curl Enhancing Smoothie* + Curl & Style Milk*, KCCC*, FSG*, CJ Pattern Pusha, Curl Keeper
Sealers: Jojoba* or Grapeseed* oil

* = HG