It is an English acronym originated in south central Indiana.
The acronym means: Please Don't Stop Going Down Balls Deep In Your Throat On Me All Day. It is never used while actually trying to gain sexual admittance to a woman, but routinely used behind an attractive woman's back. The acronym is often stated in a voice that cannot be heard by the woman but in an audible tone strangely only heard by young men in their mid to late 20's.
24 Year Old Guy: Looking across the grocery next to his buddy.
27 Year Old Guy: Same
Attractive Woman: Walks by.
27 Year Old Guy: Wow, PDSGDBDIYTOMAD!!!!
24 year old guy: BAAAAAHHAHAHAHAHAHAHAHA! F Yeah!!