From "Stay Lucky: Flameproof and Free (#4.1)"
[earlier, Thomas had accidentally seen Samantha in the shower and had teased her about a butterfly tattoo on her buttock; she offered to keep quiet about Thomas's spell in prison if he would keep quiet about the butterfly
[talking about Samantha
] Tha can put no bloody flies over that 'un, eh?
Only of the butter variety.
] As I remember correctly, we had a deal on the subject of insects and institutions.