The first time I fed my bp f/t it took him about 45 minutes before he took it but he was interested in the meal the whole time. I found that if I did the little dance with the mouse and tongs then moved it to the other side of the enclosure for a minute or two he would look around to see where it went.

I did this a few times and finally he took it. Just be careful not to stress your snake out by over-doing the "dead mouse" dance, because that could make your attempts at feeding even harder. If you have already tried a few times, give him a week before you try again and thaw the mouse on-top or near the enclosure for the day and that might help trigger some feeding response. Then try again with a similar attempt.

Hope that helps!