Condom Problem

Brother Sammy (not his real name) confessed that once he fitted on the Condom, his little brother just go limp to the extend that he can't penetrate.



However,when he perform raw, (i.e. don't wear the condom), the problem of the penis going limp does not appear. 

What could be the possible causes?

Hear say that ...Some of the condom seems to be lubricated with certain oil or chemical which "may" make your didi becomes soft after a while. Is that so?

or perhaps when we PCC, the grip is not as tight compare to the condom.

or.... In reality, no matter how we handle our dick, it will never be the same as putting on a tight condom. Tight condom will restrict the flow of blood to the penis, therefore disturbing the erection process. Sounds logical??