I too practice a customised breathing technique which is a combination of Sudarshan Kriya[1] + Wim Hof[2] while laying back on the floor.
[1] https://www.youtube.com/watch?v=0tX0M6EveGY
[2] https://www.youtube.com/watch?v=tybOi4hjZFQ
30 mins. Everyday after brush.