Haha, this question is so funny! I live in Holland, and rolling joints like that is a natural thing here, so this didn’t even cross my mind, but I’m happy to explain:
First of all, we have rolling papers available here. Like this one. That makes a big difference. We also use “tips”, which are basically self-rolled-filters, and the packs look like this. You tear one out and roll it into a small filter. We put this at the beginning of our paper. Then we use a little bit of tobacco, a little near the filter, and gradually getting more while going to the end. Then you sprinkle some ganja on there, and roll it shut. Because you have to roll around the tip (filter), the joint will get small there, and because you gradually put more towards the end, it gets wider at the end.
Then you take the joint and tap it on a hard surface, which will make more compact. If it’s too loose, too much will burn away fast when you smoke it. Then we take a cigarette filter or a key, and stamp it together some more, gently. Burn the excess paper off at the end, and voila, you have yourself a Dutch joint.
It is recommended you first practice with tobacco only, that way you don’t waste any weed.