An acronym for Double Dentry Penetration. First used by Jackson Davey, this term means that the Dentry twins (identical twins) penetrate you both at once. This may sound like incest but the idea is not to let them touch. DDP is not restricted to just penises either, hands or other objects may be used in DDP (and it can be performed on both females and males). The hotmail used by them Twinentry@hotmail.com
makes the term even funnier because it reads "Twin Entry".