You can easily regulate water intensity by exerting more or less pressure to the bottle. This way you will get perfect results, better than using toilet paper or wipes.
Turn a plastic bottle into a bidet
CuloClean is a portable gadget that turns a plastic bottle into a bidet. I can't vouch for its efficacy but it seems like a useful alternative to wiping your bum, especially as toilet paper has become a high-value currency. Apparently CuloClean supplies are also running low but it seems like you could make one yourself that would at least approximate this $9 gadget's utility. From CuloClean:
