So, if you're not using condoms on the toys, or you're not using latex condoms, oil based lubes are often the easiest to D.I.Y, because they include things like Vaseline, olive oil, and baby oil, and other oils you can find around the house (you can read more about them here:
Lube 101: A Slick Little primer). That being said, you can usually find other kinds of lube at drug stores or grocery stores, and lube is made to be body-safe, so that could also be a pretty accessible option.
I do think it's important to mention that anal sex shouldn't be painful, period. Trying anal stimulation on your own is a way to learn just how much lube you need, what pace feels right to you, and what kinds of stimulation do and don't feel good, rather than on teaching yourself to deal with or expect a certain level of pain. Does that make sense?