A very popular technique used in the multiplayer game series, Halo. This "combo" involves throwing a grenade at there feet to remove their shields partially or completely then shooting them in the head with a Magnum, Carbine, or Battle Rifle.
This is not to be confused with the "noob combo" which is shooting them with an overcharged plasma pistol and then shooting them in the face with a Magnum, Carbine, or Battle Rifle. The pro combo is much more common than the noob combo in the third Halo because of the large nurf that the plasma pistol received.
BOB: I was just about to die when my partner landed a grenade and finished off the pro combo with my BR.
Pro contact is a term that tends to float around the radqueer and radinclus community, it is referencing people who suffer with paraphilia's.
Someone who is pro contact believes that folks with paraphilia's such as pedophilia, zoophilia and necrophilia should be able to act on those thoughts without being reprimanded.
Someone who is anti contact is someone who supports folks struggling with paraphiliac thoughts but does not encourage them to act on those thoughts and often encourages people to seek psychiatric help.