theres three ways to counter a jab with a right hand. the pull counter is a version of the counter right hand over the top of a jab with an outside slip:
the difference of the pull counter is on the slip. you dont slip outside the jab to make it pass through the invisible space that you have next to your left ear and over your left shoulder.
you dont slip at all. you turn your right cheek in and jerk your head back and away in one motion:
imagine a jab being thrown at a point in space and mark it with an imaginary dot. put your head on that imaginary dot as an imaginary jab repeatedly jabs to that point. practice turning your right cheek in and jerking your head back and away as each jab reaches this imaginary dot for several reps. practice with different depths and speeds. try to get a friend or someone from your gym to throw jabs at an imaginary point in space and put your head on that point and practice this motion for several reps and ask for him to change depths and speeds as you progress.
another way to counter the jab with the right hand is a right hand with an inside slip in one motion. the right hand is a unique punch in boxing because its the only punch that causes the head to naturally slip when you throw it meaning that in addition to being a punch its also a defensive move which you use when you throw a right hand over the top of a jab. the head will naturally slip inside and make the jab pass through the invisible space that you have next to your right ear and over your right shoulder:
those are the different ways to counter a jab with the right hand. the right hand over the top of a jab with the inside slip in one motion is the fastest, or in boxing terms the most sudden, because the punches in a fight are experienced in terms of their suddenness not fastness, but the pull counter is probably the most psychological because of the way the pull counter can be used with or without a right hand. floyd likes to show a few pulls before throwing the right hand with each pull counter. each time floyd shows a pull on a jab, a fighter has to guess whether or not a right hand is going to come over it, which has the effect of paralyzing them. the psychological effect of the pull counter in general is that it makes a fighter have to guess whether he will get hit with a right hand on every jab, without having to actually throw any right hands.
the fighter who did that a lot was muhammad ali. if you like pull counters try to watch a lot of muhammad ali fights. that pull motion itself comes from ali because ali never used slips.