Bantergoose
When lads join together in jovialities and "banter" it rises to the same level as getting with girls (rangoose) and so the two are joined in glorious union. Nothing to do with geese although geese related jokes are permitted.
I had such a good time with Mike last night it was proper Bantergoose. I felt like I had got laid but it was just two heterosexual males having a good time in a heterosexual way,