Blood Hunter 10th level feature: Flow like a river

Using your advanced knowledge of hemocraft you are able to surge oxygen and blood into your muscles allowing you to preform quick actions more often and reliably. 

During your turn you may expend and then roll a hit dice (as if healing, dice rolled+CON mod) but instead of healing you take the amount rolled as damage, this damage cant be reduced by any means. Upon taking this damage you gain an additional bonus action for the turn, this ability can only be activated once each turn.