Toilet paper. The term "bog" is a British slang for the bathroom, the john, the head, the toilet. And of course, the only "roll" you are likely to find in the "bog" is made of tissue paper. Hence, "bogroll".
"Do the animals here in the zoo have a bathroom?"
"No they just use the ground."
"Well, does they even have a bogroll? You know like toilet paper?"
"No they don't need it."
"How do they clean their butties then?"
Toilet paper. Bog - toilet. Roll - roll of paper.
"Dude, I have real bad diarrhoea and we're out of bog roll, can you run down to Tesco for me?"
A bit like a "forward roll" but especially adapted for swampy areas, it was invented by Mr.Deevun Parp from the village of Cackpile in Swampshire. Since the technique afforded the traveller a clean arse at the end of his journey, the term has more recently been adopted to refer to toilet-tissue
"Give us a bogroll Deevun"