hi all. Curious cuck and need some advice

36 mwm and just got my wife her first black dildo. She had been using the emperor which is not black, about 7.5 long and 2 wide. I got her the "bam" black dildo but were not able to get in her pussy, just too thick. I still think she can get there...but needs practice with something not as fat. What do you suggest?