Blowing all the air out of your lungs and tensing your abs as tightly as possible, to the point that you can barely speak. This is generally done at pool parties or the beach, in order to look like your waist is smaller and your body fat is lower than it actually is. This is particularly used by shirtless people when a photo is being taken of them or when their crush is nearby.
Greg: Dude do you want a beer
Terry (in a quiet, strained voice): Dude I can't talk, Jenny is over there so I'm pulling a tactical ab tense.
The proper form of a verb that is both in the past and present.
Though largely unknown, this tense is good english, as recognized by the ISO (International Standards Organization)
1. The morbidly obese man "plupped" onto the couch, seductively "slupping" from his Big Gulp cup.
2. The adolescent boy metaphorically "jerzzed" at the thought of the next Star Wars film.