A particularly large tonk (vape) that is often passed around the toilets of a private school. some may say it is passed around more than Taylor swift? its name is Thomas due to the unfathomably large clouds it produces. it is usually able to hot box an entire bathroom within 3 chongs.
Simon chap can I Chong on Thomas the tonk engine - his clouds really are spectacular *teacher enters* " urm chaps, is that a Tonk Engine im seeing?" students would reply along the lines of "ah yes sir it is" and the teacher usually says something like " ooh thats dank bruv give us a couple pullies"