Trending Undercut Hairstyle Hair Style Boy Back Side Cut : They frame the face and add sharpness to men's jaw the vintage style slicked back cut can at times come off as a little bit of a caricature in. The hair on the sides and back of the head in an undercut is buzzed with a hair clipper and with a very short single clipper length. Undercut Hairstyle Hair Style Boy Back Side Cut / An undercut will help add a modern edge to any classic hairstyle.