The one that went down in our family folklore was when my late father was attempting to renew the electrical wiring(flex) for a light in our kitchen and found himself in need of a phillip's screwdriver, which we didn't have, so my late mother (a very prim and proper lady) dashed out to our neighbour's busy shop to ask if she could borrow the required article, which the neighbour duly produced and, being slightly curious, asked my mother why it was required --- my mother's breathless response, in the hearing of a shop full of customers, was "It's because my husband is putting sex in the feeling" (instead of "flex in the ceiling" !!) She was so profoundly embarrassed about it that she couldn't face back in there for about 6 months afterwards and obliged us kids to do all her shopping for her in the meantime.
I reckon that it runs in the family as I have frequently been guilty of getting my wucking murds fuddled, most recently when referring to the Falmouth Shanty Festival (in Cornwall) as the "Shalmouth Panty Festival" -- where I got the letter P from, when there is no P in the proper title, is a complete mystery. I am now terrified to refer to that festival as the wrong version just keeps wanting to come out and I have to think very carefully before mentioning it in polite conversation.