You can send a gift subscription to someone (even yourself) by viewing their profile, and then tap on the 'gift' icon.
You will be taken to the gift store and the top of the window will indicate that you are sending a gift to whatever nickname you have selected.
Scroll down and you will see the 'subscription' gifts listed, along with their cost in credits. Tap on the gift to select which subscription you would like. Gift subscriptions can be given for a one week or one month duration. Year long gifts are not available when buying with credits.
The next screen will ask you to confirm your purchase.
Be sure that you have selected the right person and gift! Gift transactions cannot be reversed or refunded.
When you are ready to send the gift, tap on the 'purchase gift' button to send the subscription.