mammary suffocation

Covering of the airways with female (sometimes fat-ass male) breast(s) for an extended period, resulting in Asphyxiation.

A common accident, seen in activities such as motorboating, BDSM, cowgirl stylecoitus and cockboob sandwiches.
As mammary suffocation requires both airways to become immersed and enveloped in plentiful amounts of adipose breast tissue, it usually involves breasts (racks,knockers,bazingas,tig ol bitties, boobies,etc.) of bat-shit epic proportions.

In recent years, popular culture has depicted mammary suffocation in such a way as to emphasize its epicly awesome nature. An unnamed survey reported 9 out of 10 men would give up their left nut, if it meant that their eventual cause of death would be via mammary suffocation.

See also: Hindenburg Disaster, For whom the cowbell tolls, rackout, Hooker Headlock

Jim: "Bro, Helga has such a big rack. I could motorboat those all day everyday."

Bob: "You say that now, but everyone else who's tried ended up dead from mammary suffocation."

Jim: "AWESOME. I'm in."