1. a mask or respirator for the nose only, allowing the mouth/tongue to be used for the servicing of presumably maloderous female genitalia. Mask is of the 'hose and bag', M42 or 'WWI' style as most protective filters are too large to be inserted in the nostrils. 2. (field expediant) a pair of BCG's (Wiley SG-1's) and two cigarette filters, field stripped, inserted in the nostrils. 3. a necessity when warming up a female for coitus who has been away from base camp (and soap/water) for 3 days plus...
Cpl. Ernie: "I got that new blond E-3 in the back of the Frankenstein last night."
Spec. Burt: "Oh yeah, how was she?"
Cpl. Ernie:"Fuck-tastic, but she smelled so bad, I needed a GASH MASK."