have used bolster to practise these asanas because I feel comfortable with them, if you don’t have bolster you can roll up two yoga mats or take pillows as a replacemnt. Some people choose to avoid yoga practice while menstruation cycle Some people find it quite relaxing to do yoga in periods It’s all depends upon of how you feel during your period, Every body is different and so the answer can’t be same for everyone it’s always better to self-assess your physical state And then decide While on