Keep your dirty talk on the boot(ship).
Inappropriate conversation in public.
When you talk to your girlfriend at the same way you talk to your friends/colleague's
Sailors talk a lot about dirty stuff.
When your girlfriend tells you to stop talking about inappropriate subjects . She will firmly say the word, boot!
If you say to her: I want to have xxx with you at Christmas dinner table when the all the family is sitting on the same table.
She will just shout, Boot.