The Sitting variation of the Bull position is a comfortable and intimate option for couples. The woman sits on her partner's lap, facing him, which allows for eye contact and emotional connection. This position also provides the woman with more control over the depth and speed of penetration, making it a great choice for those who prefer a slower, more sensual pace. However, the Sitting variation does have some limitations. As you mentioned, it offers less mobility than other positions, so it may not be ideal for those who prefer more vigorous or dynamic sex. Additionally, the man may find it challenging to maintain the upright posture for an extended period, so it's a good idea to have a supportive surface like a bed or couch nearby to lean against. To make the most of this position, the woman can lean back slightly, using her legs and arms to generate some penetration distance. This can help create a more dynamic and satisfying experience for both partners. Overall, the Sitting variation of the Bull position is a great option for couples who value comfort, intimacy, and control.