To be a Slick-dick is to send a gift to your loved one that coincidentally arrives with near perfect timing. Not something that you planned, but nonetheless something that enhances the overall experience for your partner.
In this instance the appearance of being slick would be unjustified, thus you're a Slick-dick.
Stuart sending an Easter egg making kit to Susie for her April birthday made him a "dick". Sending rollerskates that arrived just as her existing plans unravelled made Stuart a "Slick-dick".
Nickname for U.S. President Bill Clinton
earned for his ability to equivocate with words, make deals, and commit acts
which led to controversy, eventual impeachment proceedings against him.