"Ditching the Yoshi" is a euphemism from my childhood for sacrificing something, usually something precious, useful, or otherwise important, either for a short term gain or in the face of mortal peril.
The saying is derived from the ability for the player in Super Mario World to perform what is effectively a double jump, but at the expense of abandoning your trusty steed Yoshi. One would most often ditch the Yoshi to avoid falling down an bottomless pit after a poorly-timed jump. Mario would rocket to safety by pushing off of the back of his loyal companion, watching with a sense of shame and regret as those huge, baleful eyes rolled upwards in one agonizingly silent moment of acceptance and fealty.
The loss was all the more poignant if one was forced to ditch the prized Blue Yoshi, not only an endangered species but key to many shortcuts.
Ditching the Yoshi was most often accompanied by a cry of "DITCH HIM!" from all spectators. The player was obliged to respond with "BUT I LOVE HIM!" and do it anyway. The phrase first began to creep into the terminology and commentary for other video games, particularly Donkey Kong Country and its sequels, and then began to get circulation in increasingly strange and varied use.
A friend, having eaten all of the cookies, blamed it on his little brother and got away with it. When he told us about his triumph, he said "I ate all of my Mom's cookies and ditched Kevin the Yoshi."
During a birthday party, while engaged in playing with LEGO, someone asked for "one of those single cockpits with the hinge". Upon hearing that the only one available was already incorporated into a stock model on display on the bookcase, his response was "Ditch its Yoshi then," and the spaceship was dismantled for pieces.
One notable, and very literal, bleedover into real life was an attempt to treat a bicycle like a Yoshi. The plan was simple: Drive off a ramp into a very deep cement culvert, and jump off of the bicycle in midair in order to land on the other side. Let's just say it's a good thing I was wearing a helmet.
I didn't call my bike "Yoshi" anymore after that, but when I fly in my dreams, it's still in the looping, fluttering leaf-like arcs of Mario doing an extended powerglide with his cape.