How can you like sex and be asexual at the same time?
First, it's important to clear up that 'asexual' is often used as an umbrella term that covers grey-asexualities as well as strict asexuality. Because of this, there will be people that are on the asexual spectrum who experience attraction. For them (when attracted) the experience of sex may be little different from the typical allosexual one, so it is no mystery if they enjoy it the same as anyone else.
At the same time, even completely asexual people can enjoy sex (even though this accounts for a minority of asexuals). This is ultimately because sexual attraction and enjoyment of sex are two different things. Asexuals often have typical anatomy, and even a libido, and so the sensation of sex can still be pleasurable even if there is no attraction involved. As well as this, an asexual may enjoy aspects of sex that are less strictly connected to physical sensations – for example, liking to pleasure their partner or just wanting to pass the time.
One common way of explaining this is to consider, for example, a massage. A person might enjoy the physical sensation and emotional release associated with receiving a massage from someone else. They might also feel like they want to help their partner relax by giving them a massage. In fact, the giving and taking of massages in a relationship could be one way of being intimate, sharing time together, and expressing love. All of this is possible without there being 'massage attraction' present, and an asexual may find themselves feeling that massages and sex aren't all that different.