Very small. Unusually small. Like when your dad cuts a regular piece of bacon into four small pieces, and tries to convince you that you're getting more because you've got four "twidgie bacons" on your plate instead of only one piece, and because you're too young to know the difference, you think he must be right.
Used in conjunction with the word 'flomp' to describe a state of angst or surprise. May be etymologically traced as describing the groinal region of the human body.