Be chasing (one's) (own) tail American British verb phrase
Used when someone is busy to do a lot of things but achieve little and do not lead to progress
I have been chasing my tail all day, but I haven't finished any tasks.
Used when one wishes to engage in sex with someone
They admitted that they were chasing tail in the bar last night.
The verb "be" should be conjugated according to its tense.
1. A pill or tablet that is hard for someone to swallow because of its large size
2. An fact, claim, proposal, etc. that is very difficult to believe or accept
1. The vet gave my adorable puppy a horse pill and he spat it out immediately.