Where someone of petite stature can be manoeuvred quickly into different sex positions. This is usually followed by a savage pounding of the pelvic area. Chuckability is usually measured on a scale of 1-10.
Man 1: That petite girl is fit!!
Man 2: She’s got at least an 8 on the chuckability scale.
Man 3: Ha (sniggering) her pelvis would not last 5 minutes.