I am trying to remember what the bulbs look like, Dave, as I am not sure what you mean by the tassle. My usual reference site has pictures of the bulbs of most crocus - but not C. sativus :-(. Whilst I have just planted some of these myself I can't remember what they looked like.
The crocus corm dies off every year and forms a new corm on top of the old one, therefore I suspect that your 'tassle' is the remains of the old leaves and top of the corm
If no one else answeres this more positively then either go on the above advice, plant the corm on its side (yes, this is OK) or better still add a picture to your question and put me out of my missery!

The 'tassel' is probably the top of the reticulated coat which C. sativus has and is on the top of the bulb so is planted upwards. The base of all crocus (except a very few impossible to get hold on ones, is flat and naked. Ooooh!

i'd go for the thinner pointy end uppermost. I suspect that is the tassle. the ones i planted last year were flat along the base and pointy at the tip. but in doubt on its side is a good ploy as it will right itself. [even if planted upside down!]

That's been my experience. I'd also try to keep it where it isn't too cold in the winter, and can dry out in the summer. Maybe in gritty soil on the south side of a wall?