horseshoe-pillow
The act of "ultimate female-chest-sharing" by an amply-endowed lady while canoodling in bed with her snuggle-bunny. It begins with both cuddlers facing each other and the guy's re-positioning his pillow down on the bed a little ways so that he can nestle his head up underneath the gal's chin; he then gently lifts the gal's "upper" boob and settles his neck deep into her cleavage so that his face and neck are totally surrounded by the luscious warm softness of the gal's throat and bountiful chest-pillows. It has to actually be experienced to fully appreciate how truly "past heavenly" this position feels.
One of the nicest things about a horseshoe-pillow is that the gal doesn't hafta make virtually any effort herself to create it, and so she can easily perform it even if she's dead-tired --- all she has to do is merely lie on her side and allow the guy to nestle up to her chest and cradle his neck in between her boobs; he can then savor the dreamily-euphoric experience for a long period of time, even long after she's fallen fast asleep.