Thanks for the advise!Maybe fuck her before the call to reduce arousal or cheat and reduce relationship. Like I said I raised that stat early in the game.
Turns out I couldn't raise her friendship because she was already in love with me, so I removed myself from lover position, and called her like ten times with a half an hour delay. Although I raise her relationship to the max, it didn't help.
Well, in the end I somehow managed to give her futa maker. I gave her breast enlarger drug (that she gladly accept, corruption 50 seems to be the threshold), and after drug done its part I gave her futa maker, and she finally took it.