my ex's brother really really wants me

my EX and I split 7+ yrs ago. and his brother ran into me today. was nice to talk to him. we exchanged #s. jus to chat. I never Thot anything of it..

now he is texting me to send him sexy pics.. he wants to call me for phone sex!?! which I've NEVER done.. he said he's always wanted me.. since I was with his brother!!

this is very very awkward.. yet I like the attention he's giving me..

but I still think it's too weird or wrong cuz there's that "tie" there..how should I make him back off nicely without being mean. or rude. since I haven't seen him or his brother in a long time..