I wait 2 weeks after getting extensions put in before i let water come anywhere near them! I wash with diluted shampoo. I spray on a liquid leave-in & a braid spray when i'm done. No slipping.
I am in the C & G challenge, and have decided to wear cornbraids for my extensions. Its easy & quick to do myself. I wash and condition twice per week. First I put on a stocking cap, to keep the fuzz to a minimum. Then I get in the shower and shampoo with diluted Aubrey Honeysuckly rose moisturizing shampoo from a squeeze bottle. I saturate the hair under the stocking cap. Then I press all around the head to make sure the shampoo is everywhere. I stand under the shower stream and rinse, pressing the hair as the water flows. Then I add diluted conditioner Tresemme Moister w/vitamin E, and repeat the steps again. I make sure to rinse out the conditioner completely. All this while the stocking cap remains on.
I get out, wrap braids in a towel and press dry, stocking cap still on. When I finally remove the stocking cap to add my OCT, and Infusium 23 Moistur-logique, and BRX Braid spray, there's virtually no fuzz at all.
I guess this was a bit too detailed, but I hope this helps.