Sorry, is " i remember there was a potion for male" ? or the "side piece" ? My english is not good but nevertheless i think i deliver my point. isn't it?
Basically, I was referring to this:
"i wonder why dev didn't implemented using it for heather's boyfriend after MC fuck the boyfriend's side piece?"
This comes across as wanting the MC to have sex with Heather's boyfriend.
If the intent was to use the phrase "bit on the side" (explanation below) then it would incorrectly used. A girlfriend is not her boyfriend's "bit on the side".
Bit On The Side:
A sexual relationship with someone you are not married to or are engaging in a relationship with.
Another way of explaining this is a "friend with benefits" - a friend you can have sex with.