How can i dye my clothing?

i have favorite black top that i want to dye because i washed it like twice and now it looks really fadded so i want to dye it black i have used rit dye before on cotton tops but this top that i want to dye is cotton with 5% spandex and normally when dyeing clothes you have to soak them in really hot water to achieve the color to really stay in the fabric i dont know what to do because im afraid if i soak the shirt in hot water since it has spandex i dont what it to shrink what else can i do to achieve maximum color?