If it is happening regardless to where you are in the bow (near the tip, or near the frog, in the middle etc.) but only happens when you are playing a down bow, then it is most likely a technique issue. I would lean towards your second question of applying "pressure" the wrong way. The weight you are using to move the bow should be coming from a very relaxed arm, and is initiated in your back muscles. If you let your arm fall completely loose at your side, it actually feels quite heavy, and you can put a lot of weight into the bow.
My guess is that you are trying to apply pressure with either your right thumb, hand, wrist or elbow, when none of them should really be pushing or a source of pressure. This will lead to your bow arm being tense, and that tension is what causes the hops. Essentially, you are fighting yourself. To fix it, you need to relax your entire bow arm. Your shoulder could be tense, you could be gripping the bow with your hand much more forcefully than needed, if you play with your right thumb on top of the stick, you could be pressing too much with it etc. You should be relaxed, and the way you put "pressure" into the string is similar to if you were turning a doorknob counter-clockwise. That does not require tension in your hand or you to push down with your thumb, you are just rotating your lower arm.
If the hops are happening in the same spot on the bow up bow or down bow, then you could have a camber issue. If your bow has a flat spot or is warped, that place on the bow will feel problematic regardless to the direction your bow is going. If that is the case, tighten the bow to your usual playing tension, and look both "down" the bow from button to tip and "across" the bow to see if you can spot any irregularities. Small flat spots are challenging to see sometimes, but a bow maker will be able to spot them and most likely correct them. I am guessing you are experiencing a technique issue instead of a bow issue. However if it is a bow issue, you will end up fighting it and doing all sorts of weird things with your technique to try to overcome it.
If you have a mirror that is large enough that you can see your entire bow arm in it while playing, that may be helpful. Chances are if something looks awkward, it is awkward, and probably the source of your problems. Likewise, if you know some other German bow playing bassists, (I am under the impression that Italy is predominately a French bow playing nation) have them take a look at your bowing. If you can get a couple of lessons that would be great too.