One method of managing haemorrhoids is to push the offending swollen veins back into the anus with your finger, and then, when they are all back in place, leave your finger in your anus and squeeze on it. The longer you remain like this, two or three minutes, say, the better the relief management of the painful and common ailment. The procedure should be performed after each bowel movement and at other times of discomfort, whenever the opportunity arises.
Of course, haemorrhoids were quite prevalent amongst soldiers in WW1, probably caused by a combination of having to defecate very quickly, the long hours on their feet and living in the same wet and cold clothes, sometimes for many days-on-end.
So, when half the platoon are sitting around (or standing) with their fingers up the proverbial, the Lance-jack would shout them all to "Pull your fingers out and fall-in!"
So, if you can find any surviving serving infantry from WW1, you will be able to get confirmation of this.