JCB starter buttons 

"JCB starter buttons" - A woman's nipples resembling the control to start the engine on a vehicle manufactured by JCB

*Exclamations emitting from a building site probably around the Toombridge/Limavady area of Ireland* 'Look at thon!' ..'Aye JCB starter buttons sir'

JCB starter buttons by Robotkev August 20, 2013

JCB starter buttons 

used in rural Ireland to describe a woman's nipples if large

she has nipples on her like JCB starter buttons

JCB starter buttons by legques September 19, 2018