How do you do foils which are underneath and not on top?

How do you do foils which are underneath and not on top?

How To Foil Highlights 3 Ways

Hair By Chasity - Dark Brown Underneath With Light Brown On Top With Blonde Highlights & Bob Haircut! #HairByChasity #DarkBrown #LightBrown #Blonde # Highlights #FoilQueen #BobHaircut

Plow Under - Foil PL/MP, English MTG Urza's Destiny

Hair 101: A foolproof guide to Highlighting – My Hairdresser Australia

Dark brown underneath with blonde and medium brown on top :) @Regrann from @heatherstarlaa - Dark brown underneath with blonde and medium brown on top :) #btc…

HOW TO HIGHLIGHT HAIR Foil perfectly without damage!

where exactly do you put streaks? : r/HairDye

5 Foil Tips & Tricks From @the.blonde.chronicles

How To Do a Full Highlight in 20 Foils or Less, Hair Color Hacks