Since you're making me think about it, here's what I've got: Missionary is clearly out of the question.  I don't care if you're Ron goddamn Jeremy, Tab A won't reach Slot B. Borrowing from other types of planetary maneuvers, I'm thinking a gravity assist is in order:  tilt the bed in such a way that "her" head is angled toward the floor.  This would pull the panniculi out of the way. Its thigh spillage is the next obstacle.  I guess the easiest way would be positioning the legs off the end of the bed and pointed down.  Its body it's almost in the shape of an inverted "V". Now, creatures like this won't survive long without assistance as the shift in mass distribution will interfere with breathing.  Solution?  Positive pressure ventilation with a supraglottic airway.  Hopefully mother-in-law is just as qualified with that as she is with the broom. Time would still be limited once the necessary angle is achieved -- next concerns would be blood pressure and fluid accumulation at the head.  Congestive heart failure isn't kind to the lowest point of the body and I don't need to be Dr. Zoidberg to tell you that if "she" doesn't have it now, it won't be long. So now our pigfucker gets on with the ol' in-and-out as well as he can.  Might take a degree in math to figure out the geometry that will make things work but where there's a willy there's a way. And that may begin the nightmare... I mean, miracle... Of life.