SDC Stands for "Stroked Dad Club," this can be perceived two separate ways, either you stroked your dad the night before or your dad suffered from a stroke. Usually the latter but this is a judgement free zone.
Person 1 - Yo you wanna join the SDC?
Person 2 - What's the SDC?
Person 1 - Stroked Dad Club! You can either stroke your dad or take away his blood thinners!