HIPP stands for "Health Insurance Premium Payment Program". HIPP is not an entitlement program. It is a program that is set up to possibly save both you and Medicaid money by shifting the primary burned of health care costs to your typical insurance carrier.
Although each state administers it a little differently, here is how it basically works:
Once you apply for HIPP, Medicaid (MediCal in California) will determine which of the two is likely to be greater: 1) Medicaid payments to cover your health care or 2) Your typical health insurance plan premium.
If Medicaid determines that your typical health insurance monthly premium (for example you health care plan through your employer) is less than Medicaid paying for your health care, HIPP will pay your family's health insurance premiums for you (typically they will send you a reimbursement check).
This means your typical health insurance premiums are paid for, saving your family money, and your health insurance plan gets billed FIRST before Medicaid which saves Medicaid money.
Each state has it's own requirements for the HIPP program so it is probably best to go to your state's website, and do a search for "HIPP".
Link to California's HIPP Program.