1
general::
Be filled to or beyond normal capacity. For example, On her wedding day the church was bursting at the seams, or That was a wonderful meal, but I'm bursting at the seams. This expression alludes to rupturing the seams of a garment too tight for the wearer and is generally used hyperbolically. Also see COME APART AT THE SEAMS.
American Heritage Idioms
2
general::
Phrase(s): burst at the seams
1. Fig. to be very full and burst, perhaps at the seams. (Alludes to something that would burst at the seams if overfilled.) • I am so full from dinner! I’m ready to burst at the seams. • The room was so full it was bursting at the seams. 2. Fig. [for someone] to strain from holding in pride or laughter as if one might burst. • Tom nearly burst at the seams with pride. • We laughed so hard we just about burst at the seams.
McGrawhill's American Idioms And Phrasal Verbs