Hi Slush,
Just do that in one of Dillon's vials, if you have one. Add a few ml Orange crush first, that slowly add the Magic Blue, one drop at a time, and see if it pleases. Than try it out

.
It is always best to add the darker colour in minute quantities to a larger quantity of a lighter colour, as the darker colour tends to dominate.
HTH, warm regards, Wim