To strap yourself in tight using the stock seatbelt there are two typical methods:Rob Plummer said:Sabelt are the best harnesses IMHO.
Can't remember the specifics, but I once heard an instructor talk about giving the inertia reel seatbelt a tug in a certain way and getting it to lock tight around you.
Worth a try?
1. Pull hard on the seatbelt about halfway to engage the lock then squeeze the seatbelt buckle into the retainer
2. Slide seat back, buckle up, tug hard on seat belt to engage lock, hold seatbelt locked and slide seat forward into the seatbelt
Both methods require that you maintain enough tension at all times to keep the lock from disengaging.