Can I safely dilute steroid creams?

Decrease frequency. At first creams are typically used twice a day. Once the condition is under control decrease to once a day and then when possible every other day. This is called weaning, similar to when steroids are used orally. It is better to wean than use stop and restart. Stronger creams should not be used on sensitive area such as inner thighs, armpits, face , because ti can thin skin and cause stretch marks.
No need to do this! Steroids come in different classes ranging from super to low potency and within each class there are different percentages. So a super potent steroid like Clobetasol Propionate cream, 0.05% seem lower concentration then Hydrocortisone cream, 2.5% which is very low potency. There should be no need to dilute your steroid cream and you should only use the cream as prescribed by your doctor.
See below. Yes. It is best to dilute the steroid cream with another cream similar in consistency.