Short answer: when brushing hair extensions, start at the ends and work gradually upwards through the lengths, supporting the hair with one hand. Work gently near the root and do not drag the brush through the attachments.
The principle is simple: release the lower tangles first, then move upwards. Starting at the root and pulling everything down concentrates tension on the natural hair and the attachment points.
Why should you support the lengths?
Holding the hair with one hand while detangling the lower sections reduces the amount of pulling that reaches the base. This is useful with micro-rings, keratin bonds, tape-ins and wefts, because each method has a point or structure that should not become the centre of a tug.
You do not need to avoid the upper area completely. You need to reach it with control, separating strands where necessary and avoiding catching the brush on the attachments.
What type of brush should you use?
Choose a brush that detangles without requiring excessive force and allows you to work through the lengths progressively. VELVET Bamboo Brush, for example, was added to the catalogue as a brush suitable for extension care and can be used from the ends upwards.
The brand of brush does not correct an aggressive technique, however: any tool used to tear through a knot is still a tool being used badly. Patience, tragically, remains unavailable in a bottle.
When should you brush extensions?
It is useful to prevent small tangles from accumulating for days. Regular detangling reduces the need for more forceful intervention. Before sleeping in particular, the lengths should be orderly and then secured loosely: see How to sleep with hair extensions without damaging them.
After washing, avoid attacking heavily tangled hair with abrupt movements. First follow an orderly washing and drying routine: How to wash human hair extensions.
What changes with clip-ins?
Clip-in extensions can be removed and brushed separately, supporting the weft and working through the lengths. It is better to detangle them before reapplying: attaching a knotted weft to the head only forces you to pull while it is connected to the natural hair.
In summary
Ends first, roots later. Support the lengths, reduce the force reaching the attachments and do not let knots accumulate. It is a simple routine, which is precisely why it works: extensions prefer consistency to heroic Saturday-night interventions.