Never tried using the WeVibe for 90 minutes. Yeah, that might make you numb. The trouble with bein a guy and extended sex is orgasm. When one is young it's great. The most times I climaxed in one night was 7 and 12 in a 29 hour period. As a man ages he simply can't do it like that anymore so extended sex becomes more difficult. By my age (68) I can still do it once a day but sustaining an erection gets harder and harder (no pun intended).