A first and merely qualitative attempt:
Degree of concern disclaimed | Acoustic Unit | Scatologic Unit | Erotic Unit |
Significant | Hoot | Shit | Fuck |
Detectable | Whinge | Fart | Stroke |
Extreme | Holler | Sewer | Orgy |
Notes:
1) The use of toss for stroke is henceforth deprecated, due to its popular abuse as a synonym for the larger unit. It is probably not worth bothering with at all.
2) The levels of indifference within each magnitude category are conjectured to be approximately comparable across scales, but accurate determination of the conversion ratios awaits a fully comprehensive survey of the socio-linguistic-apathetic landscape, and:
3) Nobody gives that much of a Care Bear.