If he never threw up in his 2 years of life, you're probably not providing him with grass to chew. Although this is not essential for his health and wellbeing, it's still [recommended to offer a cat fresh grass][1] for the health benefits and to prevent the cat eating plants that might be toxic.

When cats lick their fur they inevitably swallow hairs, which are very hard to digest. Part of natural and healthy cat behavior is to regurgitate hairballs. [Grass acts like an emetic][2] and helps the process along. So if your cat eats and then vomits grass, it's perfectly healthy.

You can sometimes find little flower pots of cat grass in pet shops, supermarkets or flower shops. There are also cat grass kits available where you get a packet of seeds and grow your own cat grass.


  [1]: https://www.petmd.com/cat/care/evr_ct_how-to-grow-cat-grass
  [2]: https://www.hillspet.com/cat-care/nutrition-feeding/cat-grass-safety-and-information