Hm

code/modules/mob/living/carbon/alien/special/facehugger.dm

@@ -247,13 +247,13 @@
 
 /proc/CanHug(mob/living/M)
 	if(!istype(M))
-		return 0
+		return FALSE
 	if(M.stat == DEAD)
-		return 0
+		return FALSE
 	if(M.getorgan(/obj/item/organ/alien/hivenode))
-		return 0
+		return FALSE
 	if(AmBloodsucker(M))
-		return 0
+		return FALSE
 		
 	if(ismonkey(M))
 		return 1
@@ -262,9 +262,9 @@
 	if(ishuman(C) && !(SLOT_WEAR_MASK in C.dna.species.no_equip))
 		var/mob/living/carbon/human/H = C
 		if(H.is_mouth_covered(head_only = 1))
-			return 0
-		return 1
-	return 0
+			return FALSE
+		return TRUE
+	return FALSE
 
 #undef MIN_ACTIVE_TIME
 #undef MAX_ACTIVE_TIME

code/modules/mob/living/carbon/human/species_types/vampire.dm

@@ -82,7 +82,7 @@
 				to_chat(H, "<span class='notice'>You're already full!</span>")
 				return
 			//This checks whether or not they are wearing a garlic clove on their neck
-			if(sucking_checks(victim, TRUE, FALSE))
+			if(!sucking_checks(victim, TRUE, FALSE))
 				return
 			if(victim.stat == DEAD)
 				to_chat(H, "<span class='notice'>You need a living victim!</span>")
@@ -96,7 +96,7 @@
 				to_chat(H, "<span class='warning'>[victim] is blessed! You stop just in time to avoid catching fire.</span>")
 				return
 			//Here we check now for both the garlic cloves on the neck and for blood in the victims bloodstream.
-			if(sucking_checks(victim, TRUE, TRUE))
+			if(!sucking_checks(victim, TRUE, TRUE))
 				return
 			if(!do_after(H, 30, target = victim))
 				return