Stands for the "Standardized Pump Scale." A scale used to indicate a girl's hotness. The assigned numerical value is determined by estimating the amount of pumps it would take to ejaculate while having sexual intercourse with the girl. The lower the number of pumps, the hotter the girl. It should be noted that the SPS may be unreasonably skewed by the effects of alcohol or the lack of sex since high school prom.
Guy 1: Man, check out that hottie.
Guy 2: Yeah, she's at least a 6 on the SPS.
Guy 1: Yeah right, she's only a 2 unless you count the 4 courtesy pumps you'd give her just so you wouldn't feel so guilty.