Once, there was a girl who had to go for a operation. Her boyfriend and her blood type were in the same group... so he donated his blood so that she can continue with the operation...
After sometime, the 2 of them starts to have miscommunication and so as the days went by, the love between them starts to diminish.
And one day, the girlfriend asked for a breakup... so the guy was very angry and he retorted by saying "I WAnt my blood BAck~!!!"
Hence the girl went in of the toilet and came out, threw at him a bloody kotex pad and said "i'll pay u in monthly installments..."