Thank you for your question.
Please note that in young fertile women there is no such thing as a safe period. If you are sure you don't want a pregnancy you need to use a reliable and effective method of contraception that works whenever you have sex. If you do not like the sensation of condoms your wife can use the oral contraceptive pill which prevents pregnancy 99% and is 100% reversible with minimal side effects. Alternatively you can explore a huge variety of condoms and lubricants in the market. You will find different materials, sizes, colours, tastes of condoms to experiment with. Please note that failure rate with condoms alone is 15% or more so you need a back up of an alternative contraceptive if this failure rate is unacceptable.
With best wishes