the easiest way to just do your roots is...
just do them
maybe get one of those haircolour brushes if you don't already have one.
<-- been DIY haircolouring for 10+ years now.
edit - straw? i think with bleaching that's what/when you really need to worry about it. if you're dark/staying dark, i wouldn't worry so much. just use decent dye. and condition like a motherfucker.
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- + - ° GiRLie GeeK ° - + - °
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Therell be days/When Ill stray/I may appear to be/Constantly out of reach/I give in to sin/Because I like to practise what I preach