Your intention is karma. In this case your mind is trapped with sensual pleasure. So this is an attachment, this is a poison (ignorance, attachment, hatred). Unless you drop this attachment too like any other attachment, you are bound for rebirth hence you will bear corresponding suffering. Therefore it is best to do more meditation and develop medditation techniques which helps you as antidote for this. This is very tough but may be try focusing on breath or movement of stomach when u see lust is arising in the mind. I do not think this will hv serious -ve effects as bad karma because your intention is pleasure. But this an issue which we should try to resolve by strengthing our mind via meditation so that we are nearer our goal(nibbana). Keep nibbana as your goal so that u fall less for these traps. Sadhu !
Lust begets sorrow. - Buddha.