Hi Teddy,
There's a couple of ways, split the capsule into 5ml warm water and mix, then use a kids medicine syringe to administer. You don't need to stick it up far, just in is more than enough.
Alternative, which I find easier is to lube your hole, anything will do oils - coconut, olive, cream, spittle, or whatever. Insert the whole cap again doesn't have to be pushed up far. I sometimes syringe 5ml of water up afterwards, but not always.
If you do use water, make sure it's only a small volume.
I've done this for years and found whichever way, the powder/cap takes a few hours to dissolve, so it's important that you've done your no.2 ideally a couple of hours beforehand.
Regards,