Under normal circumstances, this tube opens when you swallow or yawn to equalize pressure and drain fluid. However, when you have a cold, the mucous membranes in your nose and throat swell up. This inflammation can clamp the Eustachian tube shut.

Inhale steam from a hot shower or a bowl of hot water with a towel over your head for 10–15 minutes. Adding a few drops of eucalyptus oil can further help clear nasal passages.

Pinch your nose and swallow simultaneously for a gentler pressure shift. 2. Moisture and Heat (To Loosen Mucus) Blocked ears: causes & treatment | Specsavers UK

Continuous jaw movement and swallowing while chewing sugar-free gum can help equalize pressure.

These signs may indicate acute otitis media (middle ear infection), a perforated eardrum, or cholesteatoma—all requiring medical treatment, possibly including antibiotics or myringotomy (surgical drainage).

This is the most effective way to "pop" your ears manually.