Jump for joy

I came across R.L. Burnside by way of Lightnin' Malcolm (who I caught on a WNED/PBS show last week). This Burnside video from 1978 says it all:

See my jumper, lawd, hangin' out on the line
See my jumper, lawd, hangin' out on the line
Know by that, something on my mind

Would'na been here baby, lawd, if it had'na been for you
Would'na been here baby, lawd, if it had'na been for you
Way down here, way you wanna do

Fix my supper baby, lawd, let me go to bed
Fix my supper baby, lawd, let me go to bed
This white lightnin' done gone to my head

The uninnuendoed meaning of jumper is a smock (on a clothes-line), as evidenced by just such an article of clothing being washed/starched/ironed in a couple of other blues numbers.