There are portable bidet-bottles, and also head-attachments that you can screw on to some disposable plastic water bottles.

Hibbent Portable Bidet Handy... https://www.amazon.com/dp/B07LBV1QG5?ref=ppx_pop_mob_ap_share

I got an electric one from Hibbent, it works well for me https://www.amazon.com/Hibbent-Portable-Bidet-Handy-Toilette/dp/B07LBV1QG5?th=1 Just an option