According to the Gheraṇḍa Saṃhitā, Aśvinī Mudrā and Mūla Bandha are……

maha_mudra_UB

According to such as the Gheraṇḍa Saṃhitā, Aśvinī Mudrā and Mūla Bandha
are seen as very different forms in terms of definition and application.
Regarding application, only Aśvinī Mudrā is focussed around
the repeated contraction of the anal sphincter muscles.