Linga Mudra (Mudra of Heat):

Method:
Interlock the fingers of both the hands and keep the thumb of
the left hand vertically straight and encircle it with the thumb
and the index finger of the right hand..
Specialty:
It generates heat in our body. Take milk, ghee, more water and
fruit juices in addition to practice of this mudra for much
benefits.
Time Duration:
Practice it any time you want. But don't practice it a lot as it
produces heat in the body.. It can cause sweating even in
winter if you practice it longer.
Benefits:
It stops production of phlegm and gives power to lungs
It cures severe cold and bronchial infection
It invigorates the body