The phrase "to latch onto" means to grasp or attach oneself firmly and persistently to something, often with a strong belief or conviction. Full definition
At first no milk will be produced, but by frequently attempting to pump or having your baby latch on to feed you may be able to restart lactation. (omaby.com)
When a baby is too fussy or crying, he may not latch on to breastfeed. (verywellfamily.com)
The same force that makes children latch on to their relationships when their bonds are threatened is also present in adults. (bettertherapy.com)