Mmm i remember there was a 'fad' at one time for condoms with hard nodules on them, fairly thick latex for better stimulation.. i think they stopped them as they broke too frequently! I did get fucked by one once, not really a great sensation to take, the top seemed to enjoy it more... felt like I'd been fucked by a bottlebrush, I've seen some dildos similar. Maybe something to use if you want to be sero converted as it would rip the insides of your ass really well before being seeded buy a few hot poz loads?