keep it wet, and if it does not move in 24 hours, split the halves with pointy tools, trying not to damage the coty's. Or that is the way I do it.
I abrade seeds and soak them in H2O2 before putting them in dirt or towel which as
@WildBill pointed out helps the shell soften.
I am considering direct planting after abrading and soaking. The first time I did it was this round, and there was no helmet head. It is possible that the seed shell moistens better with continuous contact with moist medium. Damn, maybe mother nature got it right again...
Da tinking cap is on...