A hickey is basically a bruise caused by biting, aggressive kissing or sucking of soft skin - and tongues can be bruised as well.
In that sense, yes, you can say that you can get a hickey on your tongue.
We found new mothers discussing how their infants give themselves "tongue hickeys" during pacifier use with emerging teeth.
When biting on things and even while sleeping, it is possible to bite the tongue. This could lead to bruising. Another way biting could lead to bruising is when trying to bite on hard things. The bruise could be caused by whatever is being bitten or by the teeth.
It is also possible to get tongue bruises in accidents. When one falls, there is a possibility of bruising, the tongue included. Eating things that are too hot could as well lead to a bruised tongue. Finally, the cause of bruising could be poor oral habits. Biting on hard things and the use of inappropriate toothbrushes could cause one to bruise.
See Etopical.com's Bruised Tongue Causes, Biting and Treatment for more info.
Without it, we'd struggle to eat, breathe and talk -- but how much do we really know about our tongues?
Here are eight fun facts, busted myths and health tips about the misunderstood organ, featured at the HuffingtonPost.com.