You can get yourself de-sensitised to airsickness but it is not a very pleasant experience. The RAF used to (and maybe still do) a de-sensitisation course which involved being strapped into a seat that was mounted on a hydraulic ram. The ram could reproduce any frequency of vertical oscillation that you were likely to experience in flight and you stayed in it until you were sick. The next day you got up, had breakfast and strapped in again; the process continued and the time between strapping in and puking increased (in theory). I know a few people who gat through flying training after going on this course, who otherwise could not have continued. The only problem one guy had was when he went on leave - after he came back to flying he was sick on the first trip and then he was OK again.
The teetering head on an R22 (yes Lu I know it's not strictly teetering) means it absorbs turbulence much better than semi-rigid rotor systems in more modern/advanced helos and it will certainly be better than a 152.