As nouns the difference between painstick and rainstick
is that painstick is {{cx|scifi|lang=en}} A weapon consisting of a baton capable of delivering a jolt of pain on contact with the body while rainstick is a hollow tube partially filled with pebbles or beans, and with small pins or thorns arranged helically on its inner surface, so that it produces a rain-like sound when upended.
painstick
English
Noun
(
en noun)
A weapon consisting of a baton capable of delivering a jolt of pain on contact with the body.
References
* Google Books: [https://www.google.com/search?biw=1280&bih=881&tbm=bks&sclient=psy-ab&q=%22painstick%22&btnG=&oq=&gs_l=&pbx=1] rainstick
Noun
(
en noun)
A hollow tube partially filled with pebbles or beans, and with small pins or thorns arranged helically on its inner surface, so that it produces a rain-like sound when upended.