I do not know about tipping after a failed negotiation, as i would be disappointed and not even think about it.
as to the condoms, you should converse with the lady of your choice about this well in advance of the party.
As to the issue of a desensitized condom, I don’t know any one who has them personally. There are some reasons a courtesan my hesitate to bring them, but if you email the ladies you are interested in and let them know it is a PE and when you plan to be there and maybe they will make a point of bringing some!
I’ve not tipped a girl on a failed negotiation…I HAVE and you SHOULD, however, tip a girl that gave you a tour of the joint if it’s your first time getting a tour…OR…if she’s showing you new amenities since the last time you were on property. Tour gets tip.
So far as the premature thing….
I’ve never heard of girls doing this, but I don’t see why they wouldn’t if it was truly an issue for you. Another option: Two-cum-party….or a girl that books by time and not activity. That way you can just give it another go if you go to quick.