how to create an item don't need a target and not disabled on attack

examples i had a potion,when i use it,i will regen 50 hp/0.5s,last 5s.when other attack me or i atk other,i'm still regen hp.

same with regen mana,or both

plz help me

there is flag for rejuvenation ability, "dispell on attack" set it to false.

plz look at this map,i uncheck it but when i'm attacked,it's stop regen.