When a woman dumps a man for a wealthy foreign guy purely for money.
Mary: see you've completed your foreign exchange
Nicola: yeah it was the best value move I've made
Both women cackle
After finishing anal penetration, the hole is gaping open. Thus the male puts the female on her head upside down with her legs spread open and the male takes a #2 into her open hole thus completing the foreign exchange.
Hey baby, want to end it with a foreign exchange?