I love it when dildo humpers know how to "anchor" their toy so that their hands are free and they can hump with impunity and total abandonment!! She's going for the full measure of the pleasure until she sounds off her "Big O Alarm!!!" Slam it Damn it!!!
I'm sure she tells her husband that she just can't cum from penis-in-vagina fucking but that would just be to help him feel a little less insecure about his inadequate size and stamina. Clearly, given a cock that fills her and stays good and hard long enough she is quite responsive and capable of PIV orgasms!