Green’s Dictionary of Slang

an impotent husband; thus bungling adj., sexually inadequate if not actually impotent.

1597		T. Deloney Pleasant Hist. of Jacke Newberie 10: The beginning of the world was the begetting of Children: and if you finde mee faulty in that occupation, turne mee out of thy bed for a bungler.
1600		J. Day Blind Beggar of Bednall-Green Act IV: I am no Bungler about a Wench.
1604		Wit of a Woman ii: I haue instruction enough for the perfecting of my worke, which if it be not like my selfe, let me bee counted a Bungler.
1675		‘Tom Farthing’ in Chappell Roxburghe Ballads (1874) II 447: Thou bungler art, Tom Farthing. Was ever Woman fumbled so, With always bobbing too and fro, Now too high, and now too low.
c.1698		B.E. Dict. Canting Crew n.p.: Bungler an unperforming Husband or Mechanic.
1707		Cibber Double Gallant IV i: We are two Women to one Man, you see; and if we shou’d both have a Fancy to have you particular, I doubt you’d make but bungling Work on’t.