In recent years, scholars such as Dr. Mallinson, have translated some texts which explain the traditional way of kundalini triggering.

Basically the method is mulabandha, uddiyāna bandha, breath retention and kechari mudra.

With the exception of kechari mudra, the method is more or less the same in Vajrayana, as explained by a Sakya Loppon.

So, in your opinion, has the true method of triggering kundalini been lost in the Eastern traditions?